The Messenger

No. 150 – December 2012 Pictoris and RS Puppis RS and Pictoris ESO 50th anniversary 50th celebrations ESO observing of programmes Allocation La Silla–QUEST Survey b ESO 50th Anniversary

A Milestone for The Messenger in ESO’s 50th Anniversary Year

Tim de Zeeuw1 nent launch of the construction of the trated book by Govert Schilling and Lars 39.3-metre diameter European Extremely Christensen (Europe to the Stars), many Large Telescope on Cerro Armazones additional images on the ESO website, 1 ESO with a projected start of operations in exhibitions and competitions, one of the about ten years’ time. Meanwhile, the latter with, as a prize, the opportunity number of Member States has increased to observe at Paranal, and a gala event In May 1974, Adriaan Blaauw launched to 14, with Brazil poised to join as the for representatives of the Member States The Messenger. He stated the goal first from outside Europe as soon as the and key contributors to ESO’s develop- explicitly: “To promote the participation Accession Agreement is ratified. ment, past and present (see the report of ESO staff in what goes on in the on p. 7, with copies of the speeches). In Organisation, especially at places of duty ESO’s mission is to design, construct and this special issue, four former Directors other than our own. Moreover, The operate powerful ground-based observ- General also contribute their reflections ­Messenger may serve to give the world ing facilities which enable astronomers on the significance of the 50th anniver- outside some impression of what hap­ to make important scientific discoveries sary: Lodewijk Woltjer (1975–1987), pens inside ESO.” Today The Messenger and to play a leading role in promoting Harry van der Laan (1988–1992), Riccardo is known the world over, and has reached and organising cooperation in astronomi- Giacconi (1993–1999) and Catherine a major milestone with the publication cal research. The achievement of these Cesarsky (1999–2007). of the current issue, number 150. It has goals would not have been possible with- certainly achieved its goal: the entire out the dedication and engagement of The need for good internal communica- ­collection gives a very interesting inside many individuals over the years, in par- tion over so many sites, together with the view of the development of ESO over ticular the motivated and highly skilled need to ensure that the community in much of its history (see also the article by ESO staff members carrying out in-house the Member States remains well informed Claus Madsen on p. 74). science, engineering and support activi- about ESO, is as valid a mission as it ties, matched by effort in technical and was in 1974, and maybe more so. While Coincidentally, this milestone occurs in scientific institutes and in industry in the many new channels of information the year of the 50th anniversary of ESO’s Member States, all of it strongly sup- exchange are now used routinely, The founding. On 5 October 1962, following ported by the governments of the Member Messenger continues to have an impor- many years of discussion and preparation, States and of that of Chile which hosts tant role. The layout and the content have a group of astronomers from Belgium, the Observatories. evolved over the years and the fraction France, Germany, the Netherlands and of scientific and technical articles has Sweden signed an international conven- Fifty years is a good anniversary at which increased, somewhat at the expense of tion that created ESO. The aim of the to take stock — to look back with pride the more informal and sometimes anec- Organisation was to build a large tele- on what has been achieved, to contem- dotal contributions in the early issues, scope in the southern hemisphere and to plate some of the detail on how it all no doubt caused by the increased size foster collaboration in astronomy. This led came to pass, and to learn from the past and complexity of the Organisation. I am to the construction of the La Silla Obser- while forging ahead into the future. The ­convinced that The Messenger will con- vatory in Chile with first light on the 3.6- anniversary has been celebrated in a tinue to have an important role, and I metre telescope obtained in 1976. The variety of ways — including a scientific strongly recommend this special edition early issues of The Messenger record the workshop (ESO@50, see the report to your attention. last steps leading to this achievement. on p. 64), a book by Claus Madsen (The Jewel on the Mountaintop) covering In the years since, The Messenger has nearly all of ESO’s history, a richly illus- Artist’s impression of the E-ELT on Armazones. faithfully chronicled how ESO’s pro- gramme expanded tremendously beyond the vision of the founding fathers. The build-up of La Silla was followed by the construction of the Paranal Observatory, Calçada ESO/L. hosting the Very Large Telescope (VLT), the VLT Interferometer and the survey ­telescopes VISTA and VST. The Atacama Pathfinder Experiment (APEX) partner- ship operating a 12-metre submillimetre antenna on Chajnantor was a precursor­ to the intercontinental partnership that is constructing the world’s largest­ radio telescope, the Atacama Large Millimeter/ submillimeter Array (ALMA), on the same site and with initial operations already started. The next giant step is the immi-

2 The Messenger 150 – December 2012 ESO 50th Anniversary

Reflections from Past Directors General Three Threads through Time

Lodewijk Woltjer national income (NNI), this growth also plan for the 39-metre telescope. In addi- implied a strengthening of the financial tion, the new instrumentation projects capacity to undertake more challenging for the VLT interferometer and for the Unit The celebration of 50 years of ESO recalls projects. The recent agreement with Telescopes of the VLT have made ESO early discussions about the purpose ­Brazil further adds to the weight of the the envy of the world and increased its of ESO. Was this only to construct a 3.6- organisation. Of course, ESO becomes science productivity by factors unimagi- metre telescope to explore the south- less European, but the cultural closeness nable three decades ago. The model of ern Milky Way, or was ESO part of the between Latin America and Europe shared instrumentation development European revival in science and technol- does not make this a very important between ESO and its Member States, ogy and, more generally, an attempt to issue. Moreover, relations with Chile have as planned in the original VLT proposal, restore its independence? When I came developed very favourably; although the has been a full success for both. The to ESO the latter aspect would gradually Chilean contribution consisted mainly technological capabilities of the institutes assume a dominant importance. Three of sites, Chilean scientists rapidly became are infinitely superior to those of only lines of evolution of ESO were started de facto members of the broader ESO thirty years ago. at that time, and it is interesting to see community. that, during the last decade, this long- ESO has demonstrated that European term ambition has more or less been The agreement between Sweden, cooperation works. The sum of its completed. The three lines involved the ­Germany and ESO made it possible ­member countries is much larger than a transformation of ESO from a limited twenty-five years ago for ESO to become simple addition would suggest. But association of the six founding countries part of the millimetre/submillimetre com- ESO’s long-term future depends not only into a pan-West-European organisation, munity that studies the cold Universe. on factual successes. As in the past, the expansion of the wavelength region This thread became more fully developed a common ideology will remain neces- covered by ESO and the development with the Atacama Large Millimeter/sub- sary. Undoubtedly the current economic of a strong European centre for astronomi- millimeter Array (ALMA) project. problems will pass after a shorter or cal science and technology. longer time. Far more serious is the risk The third thread in ESO’s evolution began of the loss of the European ideals so With the accession of Italy and Switzer- with some instrumentation projects. ­visible in different places. In this respect land thirty years ago, the representative- This activity became more extensive with it is essential that ESO take care not ness of ESO in the European context the development of the New Technology to lose Member States due to temporary was much improved and the successful Telescope, begun after the accession economic problems. ESO activities, incorporation of these countries made of Italy and Switzerland. The subsequent including the vital Fellowship programme, possible the subsequent further growth VLT approval in 1987 sealed ESO’s should continue to unite the young sci­ of the organisation to fourteen members. entry into the field of major telescope entists of the continent towards a com- Since the ESO budget is based on net technology, which has now allowed it to mon future. ESO/H. H. Heyer

La Silla Observatory at twilight.

The Messenger 150 – December 2012 3 ESO 50th Anniversary Reflections from Past Directors General

ESO from Age Fifty to Ninety

Harry van der Laan are far along. In this note I presume that that is expected to begin with the E-ELT the go-ahead light for humankind’s big- and the James Webb Space Telescope gest eye destined for Cerro Armazones has arrived. In 2002 three Directors General wrote will jump from amber to green. their reflections on the state of the organisation to mark ESO’s fortieth birth- With the survey telescopes VISTA and 2027, the sixty-five-year-old ESO: what day. Now we stand a decade later, the VST, as well as ALMA data analysis, could be the overview? and wiser (?), with the Editor’s request to prompting urgent needs for optical–­ once more reflect on our institution’s infrared information, the four VLT Unit Our beloved La Silla Observatory may prospects. I here look ahead another fif- ­Telescopes will see their coveted observ- well still have two or three highly spe­cial­ teen years to 2027 and then peer into the ing time allocated in a very ambitious, ised and stably operated telescopes. misty era between 2027 and 2052. ESO competitive environment, with a user (Remember that the Hale 5-metre tele- as a ninety year old? I dare not presume community facing high oversubscription scope on Mount Palomar is nearly sixty- that I could say anything credible about factors. Astrochemistry will flourish, five years old today). The whole of La Silla 2062, the one hundredth birthday. attracting a new breed of chemistry stu- is an opportunity for a Chilean Maecenas dents to astronomy graduate work. There to preserve this splendid place as an The period from 2002 until now is clear: will be more laboratory astrochemistry interactive cultural/educational scientific/ Claus Madsen has brilliantly written to unravel the molecular mysteries hidden technological monument. about its substance in The Jewel on the in ALMA’s data. Astrophysics and Mountaintop, Govert Schilling and Lars ­cosmology developments will increase At the Paranal Observatory I expect Lindberg Christensen have aptly illus- the pressure for VLT Interferometer the VLT to be exploited to the hilt, with trated the glory of the Jewel’s success in observing as well, by then streamlined instruments not yet conceived, but prob- Europe to the Stars. Both books also for technically unspecialised observers. ably with a greater emphasis on high-­ anticipate the excitement of the Atacama precision spectro-polarimetry. On nearby Large Millimeter/submillimeter Array During all this time, we trust that the Armazones the E-ELT will be the world’s (ALMA) to come. finesse of the E-ELT’s design will be trans- outstanding telescope, as the VLT is formed into the construction of this un­­ today. On Chajnantor the amazing sub- In the next fifteen years we may expect precedented machine by Member State millimetre array will have many observing a whole lot of ALMA discoveries: there is industries, while the first generation suite modes in numerous (sub)configurations so much unexplored parameter space of instruments is realised in the — by to satisfy ALMA’s worldwide community. now coming within reach. now — well-tested collaboration between So the prospects for the 65-year-old ESO the user community and ESO. By 2027 are breathtaking, the opportunities for The above-mentioned authors pay ample all the power of the 40-metre-class tele- ESO-community astronomers abundant, attention to the European Extremely Large scope, based on its built-in informatics the challenges for ESO staff fascinating. Telescope (E-ELT), a telescope whose and technological ingenuity, should be engineering and instrumentation design fully unfolding: the new era for astronomy There must be a catch … ESO/F. Kamphues Kamphues ESO/F.

Paranal Observatory at sunset.

4 The Messenger 150 – December 2012 Humankind from 2027 till 2052 do not want to make — between share­ Over all these questions looms the habit- holders capitalism and compassionate ability of Planet Earth for the projected ESO is an organisation owned and sup- social democracy. The former rules re­­ nine thousand million people. There is an ported by its Member States for its source flows in the process ofglobalisa ­ unmistakable change of climate occur- user community. Continuity requires the tion; the latter strives for small-scale ring, tangible on the timescale of a single commitment of governments, and the uniqueness, preservation of local charac- human lifetime, explosive on a geophysi- engagement of civil servants in Council ter and values in the process of “glocali­ cal one. Before the middle of the century, and the Finance Committee. The dedi­ sation”. The stability of holding to both countless millions of humans, now living cation of users we can practically take for is highly uncertain and therewith the in coastal areas and continental regions granted. Will all this hold then even in an cohesion and even long-term viability of bordering on deserts, may be on the additional twenty-five years? a European Union. Will it be resilient and move. Humankind’s greatest achieve- prosperous enough to maintain explora- ment, the rule of law, may be in jeopardy. Switch to another level of aggregation. tive adventures, of which ESO is a prime I appeal to fellow astronomers, while we In 2012 the confidence within many of our example? In parallel there is the support so ardently hunt down other planets Member States is eroding. There is no for pure scientific research and education and search for signs of life, to heed the political consensus about the optimum in the universities of our Member States. signals threatening our own. location on the scale — if there is such a The inflow of future generations of ESO one-dimensional choice, it is one that we users depends on their vigorous pursuit.

Riccardo Giacconi The undertaking of such an ambitious was slowly turned into a participative project (costing some six times the management approach where decisions yearly organisational budget) required the were discussed openly and reached by On the 50th anniversary of its foundation technical and scientific preparation of consensus, whenever possible. it is a pleasure to see ESO striving to the ESO staff and a rearrangement of the achieve and maintain a leadership role in organisational structure to carry it out It was fun to turn La Silla into a techni- ground-based astronomy in the world. successfully. The most important aspects cally up to date and scientifically produc- Arete is the ancient Greek term meaning of this rearrangement were those tive observatory, while using it also as “to be the best one can be”, and I hope it required to fully engage the interest and a test bed for instruments and software, will be the motto of ESO. sense of ownership of the project by the and while building, together with other staff. They included building up a sense institutions, a superb set of instruments I was Director General of ESO for only of unity in all institutional activities, and for the VLT. It was rewarding to ensure seven years from 1992 to 1999. I was a great deal of communication both verti- that even the hotel for the resident staff of lucky that they were the years in which cally and horizontally to best share Paranal was up to the same standard of the dream of the VLT, first proposed by knowledge, experience and mutual help. excellence. The satisfaction of working at Lodewijk Woltjer and initiated by Harry this high level of competence was an van der Laan, was translated into reality, The personnel policies were changed indispensable driver for the achievement and I consider those years among the to ensure recognition of performance and of our goals. more interesting in my scientific and the opening up of opportunities to some ­managerial life. of the ablest and youngest of the staff. I hope this enthusiasm will continue in the The rather autocratic style of manage- future as ESO undertakes more and more ment that had prevailed for many years ambitious projects. Arete!

Perspective on ESO’s 50 Years

Catherine Cesarsky with ESO, as some of our close friends operations in 1977. But soon, ESO were working there. ESO was then a acquired its own headquarters, near young organisation, growing under the Munich, and, more importantly, new When my husband and I decided to set- wing of its elder sibling, CERN, and it did member countries, Italy and Switzerland, tle in Europe in 1974, after a few years not even yet own a 4-metre-class tele- and new ideas and techniques. The at Caltech, we immediately made contact scope; the ESO 3.6-metre only started design and construction of the New

The Messenger 150 – December 2012 5 ESO 50th Anniversary Reflections from Past Directors General

Technology Telescope (NTT) was the first ration next March, while enjoying the performance of present instruments, turning point, and served as basis for magnificent results obtained during the such as HAWK-I and future instruments the VLT decision in 1987, even before the early science phase that is still ongoing. such as MUSE. On the VLTI, MATISSE glorious first light of the NTT. After a few will fully exploit the power of four tele- years of preparation, the VLT construc- By 2004, ESO and its Council had scopes and GRAVITY will probe space- tion went on the right path, with a solid reflected upon the future of ESO, and time close to the event horizon of the methodology inspired by space develop- had established the following strategic black hole in the centre of the Milky Way. ments. principles: retain European astronomical leadership into the era of Extremely Large The ESO strategic principles do not I was lucky to take the helm just after the Telescopes (ELTs); ensure completion ­mention the future of the La Silla Obser- inauguration of the first VLT telescope, of ALMA, and efficiently exploit its superb vatory, which was united with Paranal and could oversee the end of the deploy- scientific capabilities; maintain VLT in a and has been devoted increasingly ment of the telescopes, of the first gen­ world-leading position for another 10–15 to large programmes, and that is still eration of instruments, and of much of years by continued upgrades; exploit yielding first class science, such as the the interferometry. During those years the unique capabilities of the VLTI; lead in recent discovery of an Earth-sized planet ESO took the lead among astronomical the construction of an ELT on a competi- around α Centauri b, nor the installation observatories in the world, so that it was, tive timescale. in Paranal of two survey telescopes, as is fitting, in full adulthood for its 40th which fill a gap in ESO’s programme. birthday. It was time for new adventures, These principles guided the last years and this required an enlarged budget, of my mandate, and I am pleased to see As for the ELT, the community approved which was obtained by attracting new that they remain in practice today, with the innovative design proposed by Member States. The successive entry of Tim de Zeeuw. To ensure the competi- ­Delabre. The joining of two new Member Portugal, United Kingdom and Finland tiveness of the VLT, the construction of States, Spain and the Czech Republic, made ­possible the launch of the Atacama a set of highly sophisticated second gen- helped to fund a ­thorough study, now Large Millimeter/submillimeter Array eration instruments, both for regular completed. With the help of Austria, (ALMA) on an equal partnership with the observations and for interferometry, has which joined ESO in 2009, and Brazil United States; soon after, Japan, asso­ been launched; they have begun to be which signed an accession agreement in ciated to Taiwan, joined in. With the installed. The Adaptive Optics Facility will 2010, the programme is ready to be ALMA construction, ESO has extended transform one of the 8-metre telescopes launched. At 50, ESO is a mature organi- its wavelength range and the breadth into an adaptive telescope, by replacing sation, brimming with expertise, enthu­ of its science, and has learnt to participate the secondary mirror with an adaptive siasm and efficiency; I can only wish it a successfully in a truly worldwide project. one, and adding a laser launch facility with bright future. I am looking forward to the ALMA inaugu­ four beams, and will strongly enhance the ALMA (ESO/NAOJ/NRAO) and J. Guarda (ALMA)

ALMA antennas and the technical building on Chajnantor.

6 The Messenger 150 – December 2012 ESO 50th Anniversary

ESO 50th Anniversary Gala Dinner

Rowena Sirey1

1 ESO

To formally mark the 50th anniversary of the signing of the ESO Convention, a gala dinner was held in the Munich ­Residenz. A brief report of the event is presented and the speeches are re­ produced. The speakers were the Presi­ dent of the Council, Xavier Barcons; the German Minister for Education and Research, Prof. Dr Annette Schavan; the Bavarian State Minister for Science, Research and the Arts, Dr Wolfgang Heubisch; physics Nobel Laureate, Brian Schmidt; the current Director General, Tim de Zeeuw and the Chilean Minister of Foreign Affairs, Alfredo Moreno Charme. Figure 1. (Top) Guests seated in the Kaisersaal of Figure 2. (Bottom) The fellows and students together the Munich Residenz. with Tim de Zeeuw.

The signing of the ESO Convention by the five founding members, Belgium, France, Germany, the Netherlands and Sweden, took place on 5 October 1962. The anni- versary day itself was marked by a press release and an image of the Wolf–Rayet nebula NGC 2359 taken with FORS2. The nebula was observed by Brigitte­ Bailleul, a French freelance aerospace writer and journalist, who, as prize winner of an ESO competition, became the first member of the public to observe at Paranal.

The anniversary gala event was held the following week, on Thursday 11 Octo- ber 2012, in the Kaisersaal of the Munich Residenz, seat of the former kings of Bavaria in the centre of Munich. The ­Residenz dates back to the beginning of the 16th century and the Kaisersaal was first built in the 17th century as a large from all the Member States, Brazil and old friends and colleagues before they entertainment room. Chile. Many former and present­ members took their seats and the compère for the of ESO committees also attended, evening, Jochen Liske (Dr J) outlined Eighteen months in the planning, the gala together with prominent retired staff, for- the order of proceedings. The current was an impressive occasion that man- mer senior staff members and a selection President of the Council, Xavier Barcons, aged to capture both the warmth and of the current staff from Garching. ESO welcomed the guests. He stressed the spirit of ESO, celebrating not only the his- Fellows and Students, acting as guides, four ingredients of ESO: astronomy, tory of the organisation but also those represented the current and future gener- ­courage, cooperation and excellence. who have contributed to its present suc- ation of astronomers. Courage was shown by the visionary cess. The guests represented four astronomers from those five founding ­decades of ESO history, including three states and later by others of the remain- former Directors General: Lo Woltjer Welcomes ing nine that have since followed. Coop- (1975–1987), Harry van der Laan (1988– eration is one of the pillars that have 1992) and Catherine Cesarsky (1999– A welcome cocktail and canapés gave ­enabled these valiant astronomical ven- 2007) and current senior representatives everyone a chance to catch up with tures both within Europe and with Chile.

The Messenger 150 – December 2012 7 ESO 50th Anniversary Sirey R., Walsh J., ESO 50th Anniversary Gala Dinner

Excellence in technology, the telescopes Figure 3. Xavier Barcons and instruments built within the Member giving his welcome address. States and the competitive science ­produced by the telescopes have distin- guished ESO and are reflected by the excellence of its staff. The next step in the development of ESO will be the build- M. McCaughrean (ESA)/ESO ing of the planned European Extremely Large Telescope (E-ELT) for which funding is being secured by the Member States.

The opening was followed by a welcome speech by the Headquarters’ host and Member State, Germany, presented by the Federal Minister for Education and Research, Professor Annette Schavan. She congratulated ESO on its many achievements and expressed her pride Figure 4. Annette that Germany could play a special role Schavan conveying her welcome remarks. by hosting ESO’s Headquarters. Prof. Schavan recently visited the Paranal Observatory and had been deeply im­­ pressed by the VLT operations. She emphasised the dual roles of science and M. McCaughrean (ESA)/ESO technology that were central to ESO’s success and for the extension of the European research area as outlined in the Horizon 2020 programme.

The address by the host state of Bavaria was given by Dr Wolfgang Heubisch, the State Minister for Science, Research and the Arts. He welcomed the attend- ees to Munich and praised the fine images that ESO produces. He empha- Hubble Deep Field taken by the Hubble from employers, and especially by the sised that success lies in the combination Space Telescope of a tiny region in the Christiane Nüsslein-Volhard-Foundation. of world-class technology and excellent constellation of Ursa Majoris in December Nadine ended her presentation by scientists and that Bavaria has developed 1995 as being a defining moment. After emphasising how important it was to feel a range of facilities to make it into a world unsuccessfully trying for an internship at the trust of the people around her, and location for such activities. He closed ESO while still at school, she visited the appealed to the audience to give their by encouraging visitors to come again to observatory at La Silla when travelling support and trust to students and col- Munich to celebrate its many treasures, through Chile after finishing school. She leagues facing challenging situations. including the Oktoberfest. studied at Heidelberg­ University and the University of Cambridge and received her PhD from the Max-Planck-Institute Keynote speeches Speech by a young astronomer for Astronomy in Heidelberg. Her thesis topic was the study of the black hole After the main course had been served, After a first course had been served, in the nearby galaxy Centaurus A and its Brian Schmidt who, with Saul Perlmutter there was a short video of ESO facilities influence on the elliptical host galaxy and Adam Reiss, shared the 2011 Nobel followed by a presentation by Nadine NGC 5128. She took the data for this Prize for their discovery of an accelerated Neumayer, staff astronomer in the User study at the ESO Very Large Telescope. expansion to the local Universe, recalled Support Department. She described Nadine, a Fellow at ESO before becoming other cultural icons that also began in her travels on the long road to fulfilling her a staff member, is also the mother of 1962. From early views that astronomy is dream of becoming an astronomer. three children and her first child was born not fostered by the level of international ­Entitled “Reaching for the Stars”, she during her PhD years. She described co-operation practiced by ESO, he de­­ related childhood memories of lying out how challenging this combination was. scribed how, from his astronomical expe- under the stars in her home in Baden- She praised the support of her family rience, ESO had progressed and how Württemberg looking up at the sky. She and colleagues and the assistance she his perspective had changed. He recalled particularly remembers the release of the received through organised childcare, the roles of the New Technology Tele-

8 The Messenger 150 – December 2012 Figure 5. Brian Schmidt Dutch astronomer Christiaan Huygens on presenting his keynote the need to pay attention to wider issues speech. and how the recent invention of the tele- scope can expand our vision.

M. McCaughrean (ESA)/ESO Closing ceremonies

The official delegates of all the Member States then signed the surface of an E-ELT mirror blank that had been brought to the Residenz for the occasion. Their signatures have since been engraved into the mirror blank as a remembrance of the gala event and the 50 years it cele- brated. The Minister of Foreign Affairs for scope (NTT), and later the VLT, and the ­tribute to the previous Directors General, Chile, Alfredo Moreno, than expressed role of two ESO staff members, Bruno and all the staff in bringing about these his appreciation of the wonderful science Leibundgut and Jason Spyromilio, in the changes; and to the very supportive being done under the Chilean skies. collection of the crucial data on the role of Chile in hosting the observatories. Alfredo Moreno has been closely associ- acceleration of the expansion of the Uni- He noted that next year adds another ated with ESO for more than 15 years verse for the High-z Supernova Search 50th anniversary, that of the presence of and was involved in the resolution of land team. These data eventually contributed ESO in Chile. While collaboration has dispute on Cerro Paranal in 1995–6, and to the award of the Nobel Prize. He allowed so much to be achieved, we his engagement illustrates the supportive closed by commending the governments should not forget that a spirit of competi- environment referred to by the Director that have invested in ESO, enabling it to tion still drives our scientific ventures. General in his speech. achieve its current place at the peak of Even if the mysteries of dark matter and world astronomy. dark energy were to be solved soon, Finally Xavier Barcons wound up with other great challenges lie in wait and some closing remarks. He exhorted While observing that 50 years is minute extrasolar planets will remain an abiding all the Ministers and representatives of in terms of astronomical timescales, the topic. Looking to the future and to the the ESO Member States present to current Director General, Tim de Zeeuw, critical importance for the future of man- be the proud ambassadors of ESO and celebrated the enormous developments kind of society continuing to value sci- its activities. He closed by wishing ESO since the founding of ESO. He paid ence, Professor de Zeeuw quoted the a most successful next 50 years.

Figure 6. Group ­photograph of all the official representatives of the ESO Member States, the host nation Chile and the Director General.

The Messenger 150 – December 2012 9 ESO 50th Anniversary Sirey R., Walsh J., ESO 50th Anniversary Gala Dinner

Texts of Speeches

Welcome About one decade ago, ESO took a crucial step for- – The way ESO handles industrial return, and con­ ward by going into radio astronomy with APEX and sequently the generation of R&D-based activity Xavier Barcons, President of ESO Council ALMA. Today, with ALMA fully integrated into the in the Member States, is also largely based in programme and with North American and East Asian excellence criteria. Of course, a healthy industrial partners, ESO has consolidated its leadership in geo-return is also actively pursued by ESO man- Dear Ministers and dignitaries, dear Guests, ground-based astronomy, by expanding on its wave- agement and carefully monitored by ESO’s Finance ­Colleagues and Friends, length coverage, from the classical optical domain Committee and Council. into the infrared and now into millimetre and submilli- – ESO also looks for excellence when it comes to Welcome to this event that marks 50 years of ESO, metre radio astronomy. hiring its staff. It is ESO’s obligation to target the the European Organisation for Astronomical Research best professionals, so the mission charged to the in the Southern Hemisphere. Today we ­celebrate The next development is the European Extrmely Organisation by the governments of the Member together a number of things. To start with, we cele- Large Telescope (E-ELT) to which I will return later. States, can be successfully accomplished. Here, brate astronomy, perhaps the most ancient of we must be proud of the success of ESO, which the sciences and surely among the most capti­vating There is no doubt that ESO is a success, and there has a fully dedicated, professional and engaged ones. We also celebrate recent achievements in is plenty of evidence for it, in particular: staff complement. astronomy, made with the help of ESO: – ESO delivers the highest-quality astronomical data – Knowledge of hundreds of planets orbiting stars to astronomers, who bid in fierce competition for Astronomy, courage, cooperation and excellence: far from our Solar System, which only two decades observing time. these are the perfect ingredients to build the most ago belonged to the realm of science fiction. – ESO’s facilities offer the most advanced instrumen- successful future for ESO. – Progress made during the last 50 years towards tation, largely built in cooperation with institutions our understanding on how stars, planetary sys- from Member States. Several years ago, ESO Council approved how the tems and galaxies form and evolve. – ESO is the European forum where important deci- principles stated in the Convention would need to be – A serious hiccup in the widely accepted cosmo­ sions on ground-based astronomy can not only be realised during the first quarter of the 21st century. logical model that occurred in the last 15 years discussed, but adopted and eventually imple- This consists of three elements: when astronomers found that the Universe is mented. – Keeping Paranal at the forefront of optical and expanding faster and faster as time goes by. infrared ground-based astronomy through the next decade. The VLT is the most powerful observatory These and many other discoveries, as well as the Cooperation in the world, and this needs to be preserved by many questions that astronomical investigations keeping it operational and with state-of-the-art have raised, continue to be at the focus of intellec- Cooperation is certainly one of the main pillars upon instruments. tual interest of our society. The response of ESO’s which ESO’s success rests, and a major reason for – Building and exploiting ALMA together with ESO’s Member States to this quest has been to build our celebration today: international partners. ALMA construction is not and operate world-class astronomical observatories – Cooperation amongst ESO Member States is yet over, but we can see it coming closer. In March and to foster cooperation in astronomical research. probably best seen at ESO Council. Delegations next year, ALMA will be inaugurated by Chilean have made continuous progress together during President Sebastián Piñera, along with ministers A little more than five decades ago, a group of the last 50 years, often putting aside national inter- and dignitaries of ESO’s Member States and of our visionary European astronomers succeeded in ests for the benefit of the full ESO. North American and East Asian partners. In the ­promoting the idea of building a 3-metre-class tele- – ESO’s Member States today encompass the vast meantime, Early ­Science observations with a majority of European astronomers, who, through scope in a new observatory to be placed in the reduced version of ALMA are showing astonishing cooperation with ESO, devote the best of their southern hemisphere. The governments of Belgium, results and ­giving a glimpse of what a fully devel- efforts to secure a most advanced suite of instru- France, Germany, the Netherlands and Sweden were oped array with 66 ALMA antennas will bring. ments for our telescopes and the best possible brave enough to sign the Convention establishing – The third element is to build an Extremely Large science output of the facilities. a European Organisation for Astronomical Research Telescope that will keep Europe at the forefront – The same spirit of cooperation was also the driving in the Southern Hemisphere. ESO soon after signed of optical ground-based astronomy in the 2020s force behind the signature in November 1963 of the first agreement with the Republic of Chile to and beyond. the first site agreement between ESO and Chile, establish its observatories in that country, opening a which allowed ESO’s telescopes to be deployed long-lasting and successful collaboration. ESO, together with European industry, has ­produced there. a solid detailed design of the most powerful, and – Cooperation is also behind the ALMA agreements yet affordable, E-ELT. A number of reviews have between ESO and its ALMA partners in North Courage shown that ESO is technically and programmatically America and East Asia. Let us not forget that ALMA ready to start the construction of this 39-metre giant is the very first global ground-based infrastructure Today we celebrate the courage of those visionary telescope, provided that the funds are available. of its size without a leading partner. We are well astronomers, of the five governments that started aware that we are being carefully watched by large ESO and of the remaining nine that have joined At the moment, seven of our Member States have projects in other areas which are coming next. since: Denmark, Italy, Switzerland, Portugal, the solidly committed to the project, and this needs United Kingdom, Finland, Spain, the Czech Republic to be recognised and appreciated. But the target is and Austria. In addition we all encourage the efforts to have all ESO Member States joining the E-ELT, Excellence of the Brazilian government towards successful including Brazil as ESO’s 15th Member State. I am well aware that all ESO Member States are working ­conclusion of the ratification process, after which Looking for excellence is the guiding principle in the hard to be able to participate in the E-ELT, despite Brazil will become ESO’s 15th Member State. way that ESO works, something more to celebrate the current financial environment. But, the E-ELT today: is a project that will produce, in the short term, R&D ESO has experienced huge changes during those – ESO’s telescopes are amongst the most advanced activity in the industries of the Member States, 50 years, and they are particularly evident during in the world and placed in some of the best sites a much-needed ingredient to overcome the current the last couple of decades. Almost two decades for astronomical observing. financial crisis. In the long term, it will ensure that ago, and with La Silla firmly established as ESO’s – ESO’s telescopes are highly demanded by the sci- ESO’s Member States will remain at the forefront of observatory in Chile with its 3.6-metre telescope entists; typically they request five times more astronomy. Together, we can make it happen. among others, came the building and deployment observing time than is actually available. The of the Very Large Telescope, the VLT, the most pow- choice of those projects that actually make it to the erful optical observatory in the world; later the VLTI telescopes is based on scientific excellence. This Dear Ministers and dignitaries, dear guests. Thank interferometer — a unique facility — and more has resulted in the astronomical researchers in all you very much for coming and joining the big ESO recently the survey telescopes VST and VISTA, all our Member States becoming more competitive, family tonight. And now, enjoy the celebrations. of them on Cerro Paranal. ESO’s Paranal Observa- leading to the best possible science return from tory is undisputedly the world’s most powerful astro­ ESO’s sophisticated and expensive infrastructures. nomical observatory in the optical and near-infrared.

10 The Messenger 150 – December 2012 Welcome Remarks week for us all, for scientists and for science politi- and America. The financialcrisis ­ shows us that cians. He will tell us more about this great research we must make further efforts for Europe to stay suc- Annette Schavan, German Federal Minister for success. Welcome, and we are looking forward to cessful in the future. This is the major issue in the Education and Research hearing you. context of Horizon 2020. Germany has tried to trans- late the German high-tech strategy to the European- We in Germany are proud to be among the ESO wide Horizon 2020 in order to focus on the entire Dear Guests, Excellencies, Ambassadors, Mr Presi- Member States. We are also fully involved with our information chain, as we have been doing in Germany dent, dear Colleagues, Ladies and ­Gentlemen, special responsibility as host country and have greatly since 2006. This will distinguish the new research contributed to the Headquarters extension building in Framework Programme from the former ones. The Welcome to Germany. It is a great pleasure for me Garching. We support the ambitious but very realistic close network of science,­ research and innovation is to have you here for this very special anniversary. It objective that research conducted at ESO is at world- a key to both economic success and social coher- is almost 50 years to the day since the establishment class level. We want it to stay that way. ence: the bold way to provide young people in of the European Southern Observatory marked the Europe with a positive argument for the future. In the beginning of the present success story. The five We realise that the construction of the European 21st century the European Union must become a founding states of ESO, have ­meanwhile grown to Extremely Large Telescope will be decisive in main- union of innovation — that will be our great wish for 14 and, as we are deeply convinced, 15, on the taining European leadership role in this field. We the scope of Horizon 2020. This also provides the accession of Brazil. Today ESO is a world-leading need the European leadership role. The ­performance opportunity to build new bridges between people in and certainly most productive institution for ground- of the E-ELT will be revolutionary and will provide Europe on the topics of education and science, based astronomical research. We are all pleased answers to some of the most pressing questions in research and development. We must bear in mind about this outstanding scientific development, which astrophysics. Let’s jointly make sure that these the words of John Lee, “We don’t unite states — we is a confirmation of the excellent productivity of this important findings are European findings. European unite people.” partnership. astronomy has resumed its leadership position on a sound base of cooperation. In particular in the The integration of research and innovation with A few days ago I visited one of the unique observa- challenging times we face in Europe, ESO’s achieve- nationality has been remarkably successful in ESO, tion locations — the observatory of Cerro Paranal ments remind us of what we can achieve jointly. making it a model for the burgeoning European sci- in Chile. I was deeply impressed, and with the Direc- ence community, which actively contributes to the tor General and the German delegation it was a Cooperation in science and research points the way process of integration. great pleasure to witness this special place. I was to Europe’s continued success in the future. deeply impressed by my visit to the Very Large Tele- On this 50th anniversary of its founding I would scope there. It is no coincidence that the VLT is an Research in science is, I am deeply convinced, the like to congratulate the European Southern Observa- optical telescope with the best performance world- sole basis for the future of our society. Europe’s tory for all its achievements to date. I would like to wide. It stands for the international importance of real wealth lies in the skills and intellectual potential thank your staff, your partners and the scientists the entire organisation. All three locations of ESO in of its people. That is very important for the further who have always made sure that ESO users are able Chile are operating equipment which is one of a development of the European Research Area (ERA) to work at a high level and at the cutting-edge of kind, and is greatly in demand by astronomers from and to understand it, not only as an instrument astronomical research and will continue to do so by all over the world. of research, but quite specifically as part of the Euro- designing, building and operating telescopes and pean process of integration. instrumentation. I would like also to thank our inter- The most recent Nobel Prize for Physics, which national ­partners who laid the foundations of this was awarded for the discovery of the accelerating In addition to the prize ERA initiatives since 2008, success story together. Let’s continue along these expansion of the Universe, was based on data the European research Framework Programme has lines together. obtained from ESO. I believe the Nobel Laureate also brought this process forward. Scientists from Prof. Brian Schmidt will tell us about this special all over Europe are cooperating in the most diverse So once more welcome to Germany and congratula- theme for scientists — since Monday a very special projects, sometimes even with researchers in Asia tions to ESO.

Welcome Remarks far-sighted decision to let an alliance of countries Bavaria’s fertile research landscape is based on work together in order to further progress. Fourteen a sophisticated network of state-of-the-art facilities Wolfgang Heubisch, Bavarian State Minister for — and soon fifteen — countries from Europe and including nine state universities, seventeen state Science, Research and the Arts beyond are joining their efforts to realise unique and ­universities of applied sciences, thirteen Max Planck pioneering projects in astronomy. Institutes, five research facilities of the Leibniz ­Society, several institutes of the Fraunhofer Society Dear Professors Schavan, Barcons and de Zeeuw, Today, ESO is the foremost intergovernmental and many other renowned non-university research Vice Minister Wilhelm, State Secretary astronomy organisation in the world. It operates facilities. Dell’Ambrogio, your Excellencies, Ladies and three world-class observing sites in Chile. Its ­Gentlemen, ­powerful facilities give astronomers the necessary Within this rich research landscape, ESO is an instruments to make discoveries which lead to outstanding and precious landmark. It contributes On behalf of the Bavarian State Ministry for Science, new insights and a deeper understanding of the to Bavaria’s reputation as an important site for Research and the Arts, it is my pleasure to welcome ­Universe. It is no wonder that the discovery of the ­science and it attracts a large number of top scien- you to the Munich Residenz. Together, we want to accelerating expansion of the Universe was based tists from around the globe. They enrich research celebrate the 50th anniversary of ESO. The Prime in part on data taken with ESO telescopes. For this in Bavaria with their expertise and excellence. Minister of Bavaria, Horst Seehofer, regrets that he is breakthrough finding, the Nobel Prize for Physics Bavaria also benefits from ESO because a good part not able to join us tonight and sends his best was awarded to Saul Perlmutter, Brian Schmidt, and of the ESO budget is invested in Garching: about regards. Adam Riess in 2011. Two ESO staff members (Bruno 30 million euros per year. Moreover, within the last Leibundgut and Jason Spyromilio) worked in the ten years ESO concluded contracts in the high-tech Curiosity is at the basis of research. It is the driving team of Schmidt and Riess. Once again we see that sector in Bavaria and Germany amounting to 100 force for discoveries and inventions. [The Mars success lies in the combination of both world-class million euros. ­Science Laboratory Curiosity: demonstrates what technology and excellent scientists. curious scientists and researchers can achieve As an international research organisation, ESO and provides us with fascinating colour images of This is also why Bavaria has developed into a first- knows about the importance of EU research the red planet.] The success of ESO is due to the rate international location for science and research. ­programmes and funding. In 2011, the organisation

The Messenger 150 – December 2012 11 ESO 50th Anniversary Sirey R., Walsh J., ESO 50th Anniversary Gala Dinner

participated in seven EU 7th Framework Programme a budget of 80 billion euros to fund research and Bavaria as a key location for science and industry. projects. Bavaria also profits greatly from EU innovation over a span of seven years. One of the Thank you very much for your dedication and com- research funds. In the last few years, the Bavarian priorities that Horizon 2020 will focus on is excel- mitment. Keep on being curious and contributing to universities alone received the remarkable amount lence. It is my firm belief that to secure Europe’s new and groundbreaking discoveries. of more than 70 million euros per year. long-term competitiveness, we need to raise and strengthen the level of excellence. I am looking forward to an interesting evening and Research and innovation are at the core of the wish all of us a fruitful exchange of ideas and views. Europe 2020 strategy and its flagship initiative, Inno- Dear ESO staff, And for those guests who have come from far away: vation Union, because research and innovation Fifty years of working together to uncover the mys- I hope that you also find some time in the next few help to create new jobs and prosperity, and to turn teries and secrets of our Universe: I congratulate days to discover and enjoy the natural and cultural ideas into social progress. The next framework you on that. With courage, passion and persever- gems that Bavaria has to offer. Enjoy your dinner! ­programme — Horizon 2020 — goes in the same ance you make it possible to further astronomical direction. It is expected to start in 2014 and to have research. Your excellent work also strengthens

Keynote Speech As someone who grew up in the United States, the Today ESO is no longer dismissed as some irrelevant European way of doing things was a bit foreign — European organisation by anyone in the world. Brian Schmidt, Physics Nobel Prize Laureate, 2011 and not just to me, but to my entire country. Why Rather it is often referred to as “Gold Plated” or “The would anyone wish to go through the effort to bring Observatory that God would have built, if only He together so many cultures through the complexity or She had enough money”. I had the chance on my Meine Damen und Herren, Senoras y Senores, Hyvät of an inter-governmental treaty? Why not just go out way to this celebration to visit Paranal­ for the first naiset ja herrat, Dames en heren, Dámy a pánové, and do it, one piece and one country at a time? time. What I saw was not decadence, except possi- Signore e signori, Mine damer og herrer, Senhoras e These were my ­attitudes to ESO when I started my bly for a few fake rocks put in place for the last senhores, Mina damer och herrar, Mesdames et PhD in 1989. I had failed to understand that ESO James Bond movie. Instead, what I saw gave me far Messieurs, Ladies and Gentlemen. was not built around a single era of telescope, living more than a quantum of solace that ESO’s resources a golden age and then fading into obscurity. Rather were being well deployed. I saw an amazing obser- While ESO is an institution of many languages, it is it was an observatory always with one foot in the vatory — one with a scale that enables efficiencies the place where people from around the world come present and one foot in the future. of operations that make other observatories envious. together to speak astronomy. I saw a vigorous investment in the future, with My first glimpse of what was possible came with the new instruments being brought online unlike any- On 5 October 1962, the Beatles released their first New Technology Telescope — the NTT — which, where else in the world. After all, a telescope is only single, Love Me Do. Dr No premiered on this same true to its name, employed all sorts of new technol- as good as the instruments on it, and it only makes day, starting the James Bond franchise and helping ogy to help the telescope obtain higher quality data. sense to ensure a constant supply of cutting-edge make all of us order our Martinis “shaken not Starting in 1990, we began seeing press reports that instrumentation on your flagship facilities. stirred”. But it is the birth of the European Southern talked about phenomenal image quality — too good Observatory that we celebrate today — a scientific to be true, we thought; it cannot possibly be that This strategic ability to plan is at the core of ESO’s organisation whose discoveries will ensure that it good — there must be a catch. But it was that image ascension to the pinnacle of world observatories, is the longest remembered of these cultural icons quality that both made possible the discovery of the and this same structure enables ESO to run its first born on that faithful and rather remarkable Sunday black hole in the centre of the Milky Way, and as it generation facilities on La Silla more efficiently and in 1962. turns out, saved the High-z Supernova Search Team. cheaper than any other comparable observatory. The ESO structure has also allowed forays into new That is — as big a Beatles fan that I am (I have owned In 1994, my colleagues and I formed the High-z exciting areas — like the ALMA telescope, currently all the albums since I was a kid), and as much as I Supernova Search Team — a collection of astrono- being deployed. Despite millimetre-wavelength am looking forward to SkyFall, the next James Bond mers interested in supernovae — wanting to take astronomy being previously largely foreign to ESO, film (and yes, I have seen every James Bond film — advantage of the opportunity to use Type i a super- ESO, by engaging with industrial partners, and the the good and the bad), I am sure that the discovery, novae to measure the change in the expansion vast array of European univer­sities and research for example, of the supermassive black hole in our rate of the Universe. We took our first data in 1995, institutes, has managed to quickly catch up. Using Galaxy’s centre will ­outlast them both. And so I say but finding supernovae was not as easy a task as I its ability to plan, it already has a second generation ESO is a great cultural icon — because astronomy had hoped, made even harder by my foolish decision instrument in the works for this newest of its tele- is more than just science — it is an expression of to try to orchestrate a search from Australia with scopes. While this planning may have surprised its humanity to understand our place in the Universe — ­virgin software through an internet connection that partners, it is only sensible to plan upgrades to an understanding which is shared across the world, was one character per second. ALMA so that the initial capital investment in the tel- and a science which dates back to the beginnings of escope will pay healthy scientific dividends into the civilisation — and probably before. When all seemed lost and it seemed that our ­project future. would fizzle without finding a single ex­­ploding star, Astronomy is ultimately empowered by telescopes, we found an object at the last pos­sible moment. This ESO is now embarking on its most ambitious project­ and the technology behind them. To make progress, object — it looked like a supernova on our images — yet — the European Extremely Large Telescope it is necessary to marry good ideas with cutting- but the all-important confirming spectrum evaded (E-ELT). A project that is no longer just in step with edge equipment — equipment that can exceed the us. Our last chance was with Bruno Leibundgut and the rest of the world, but rather a step ahead. ability of a single nation to afford. The sky has no Jason Spyromilio on the NTT, and through the great Although the E-ELT is the most formidable of the owners and no measurable bounds — and as such, image quality of the telescope and the amazing next generation of telescopes, its design is already astronomers are born to collaborate. Conceived in ­persistence of these two astronomers, a spectrum the most technically advanced. I have no doubt it will 1954, born in 1962, ESO was an approach for five was obtained, revealing this as the most distant be a success. There is no doubt that as the E-ELT countries to be able to better do astronomy — by supernova then detected. The High-z team was nears completion in the future, ESO will be able to combining together the resources and ideas of many saved. ESO facilities continued to play a pivotal role plan the next big thing — be it another optical tele- into a much greater whole. Although this was a in our programme up to and well beyond the scope, next generation gravity-wave telescope, or a new way of doing things in astronomy, it was not a ­discovery of acceleration in 1998 with these super- huge radio telescope — it is uniquely able to formu- new way of doing things in Europe, as ESO was novae. late a portfolio of facilities for its members. It is for clearly born out of the ideas surrounding CERN — this reason that the Australian astronomical commu- ESO’s highly successful scientific sibling. nity, in our ­latest report to our government, have

12 The Messenger 150 – December 2012 advocated that Australia join ESO with its highest astronomy is bright at ESO, instead, I see that the community it serves, to achieve an impressive rise priority. Of course we still have the challenging task future of astronomy is ESO. over the last 50 years to its current magnificent state of convincing our government that it should invest at the top of world astronomy. ESO is poised to in ESO, as well as ensuring that ESO itself would like So on that note, I would like to commend the continue to thrive into the future, providing the world us as a member. But as I contemplate the future ­governments that have invested in ESO. Your invest- with an exciting and wonderful look into our Uni- of astronomy — I do not just see that the future of ment has enabled the staff of ESO, and the broader verse. Happy 50th Birthday!

Keynote Speech I want to emphasise the key role of Chile. After the I hope we can crack the problem of dark matter and initial idea to go to Namibia or South Africa, the dark energy. The excitement in the exoplanet field Tim de Zeeuw, ESO Director General clear skies of Chile quickly became irresistible, and I is only just starting and will no doubt continue for am pleased to note that next year we will not only decades. This new field addresses questions that inaugurate ALMA with our intercontinental partners transcend astronomy and even science, as it con- ESO’s Past, Present and Future on 13 March, but also, in early November, celebrate nects with the bigger question of the origin of biolog- 50 years of ESO’s presence in Chile. The govern- ical activity and the presence of life elsewhere in Your Excellencies, Delegates, former Directors ment of Chile has been very supportive of ESO, and the Universe. As Dire Straits put it: So many different ­General, other luminaries, colleagues and friends, it is a singular honour that the Foreign Minister, worlds, so many different Suns. The E-ELT has a big Chancellor Alfredo Moreno, is with us today. He had role to play here! It is a great pleasure and privilege to be at the helm a personal hand in valuing the Paranal property of ESO and to be able to address you on this special ­during a difficult episode in the mid-1990s, and he Looking further ahead, it is critical that our society occasion. was instrumental in the generous gift by Chile one remains interested in science. I am always pleased year ago to extend the Paranal property to the east, to see people being excited about their latest app Since the founding of ESO, the Earth has been to contain Cerro Armazones, where the E-ELT will be which allows them to see what’s happening in the 50 times around the Sun, Jupiter only four times, constructed soon. sky. But few realise this application requires an and Saturn a little over 1.5 times. The Sun itself astronomer and a skilled software engineer to make has covered one-fifth of one millionth of its orbit ESO is an excellent example of the benefits of it work. If we stop doing science and only watch around the centre of the Milky Way. So fifty years is ­collaboration, but we should not forget the advan- reality shows, our society is doomed. This is why a tiny period on cosmic scales, yet astronomy has tages of healthy competition. Examples include ESO and many other scientific institutions have progressed at an unprecedented pace. ESO can the discovery of the accelerating Universe, the active outreach programmes to inspire young people be proud to be an integral part of the many discover- search for exoplanets and the irrefutable evidence and emphasise the importance of fundamental sci- ies that clearly fascinate young and old across the for a giant black hole in the centre of our Milky Way. ence for society. world. In all cases there has been intense but fruitful ­competition between teams using different ground- To conclude, let me quote: No doubt many will say Over these fifty years, ESO has expanded far beyond based telescopes and instruments. This allowed that I am overly fascinated by matters which barely the dreams of its founding fathers. This has been the teams to get to the scientific results sooner and touch us, while there is so much else to investigate made possible by the strong support of the Member to have their conclusions accepted by the commu- closer to home. You might think this is a recent States and Chile, by the previous Directors General nity, and was also very beneficial for pushing the quote from a spokesperson of a ministry of economic and by the motivated and highly skilled staff. observatories to stay at the leading edge. For these affairs only interested in short term results with reasons it is my firm belief that ESO should not immediate financial advantage. In fact, it is taken The DGs Otto Heckmann and Adriaan Blaauw laid become a “world lab” where a few giant teams work from the dedication of Christiaan Huygens’ book the foundations of ESO and built La Silla. Unfortu- on a small number of focused experiments. on the Saturnian System, in 1659, presented to nately they are no longer with us, although Adriaan Prince Leopold of Tuscany, and written in difficult visited La Silla and Paranal two and a half years And this brings me to the future. Much of the truly financial times. ago, at age 95. I am very pleased that Lo Woltjer, tremendous progress in our field has come from the Harry van der Laan and Catherine Cesarsky are huge developments over a wide range of technolo- Huygens goes on to say: Few seem to realise that here. Riccardo Giacconi has sent warm congratula- gies. Astronomy has very happily taken advantage the study of the heavens surpasses all other tions. Lo had the vision of the Very Large Telescope of these, and sometimes pushed them, all with the ­endeavours. If we think that what is far away is not and Harry and Riccardo oversaw its construction. goal to build better and better telescopes. We important for us, then our mind is without any doubt Catherine developed ESO’s role in ALMA, and man- should continue to do so, in close collaboration with unworthy of the enlightenment provided by the pure aged the early planning­ for what is going to be high-tech industry. reasoning that transcends even the immensity of the E-ELT. In the process ESO grew to 14 Member the Universe. And we also do not deserve to take States, with Brazil poised to be the fifteenth. I am convinced that new scientific questions will advantage of the invaluable invention of the means to Together these countries represent 30% of the continue to emerge. Fifty years ago we had no ink- improve our vision to be able to reach the realm of world’s astronomers. What a change! ling that we would find that the expansion of the the stars. ­Universe was speeding up — as Brian just de­­ This entire development is captured in two excellent scribed. Although finding evidence for planets orbit- I hope I have convinced you that Huygens’ words of books commissioned for this special year. Europe to ing other stars was a dream for centuries, the tech- 350 years ago are as true as ever. This bodes well the Stars by Govert Schilling and Lars Christensen, nology to find them didn’t become available until the for ESO’s future. Thank you. and The Jewel on the Mountaintop by Claus Madsen. 1990s. Arguing by analogy, there will no doubt They contain beautiful images, as well as many of be big surprises and probably major paradigm shifts. the stories, and some of the legends, that made ESO As the Greek philosopher Heraclitus stated 2500 what it is today. years ago: If you do not expect the unexpected, you will not find it.

The Messenger 150 – December 2012 13 ESO 50th Anniversary Sirey R., Walsh J., ESO 50th Anniversary Gala Dinner

Speech of Thanks report to the Chilean Senate, I stated the probability in Chile. We are fully aware of the opportunities of having a very large observatory on that mountain and challenges that these observatories bring to us. Alfredo Moreno Charme, Chilean Minister of peak in a few years. That was in 1995. The Chilean We will continue to work with you in the scientific ­Foreign Affairs Senate approved unanimously the high price to be field but also collaborate with the engineering, inno- paid for Paranal. This price was related to the enor- vative and technological challenges ahead. mous value of the site. In the near future on that little As mentioned before, almost 20 years ago I was peak of Armazones the E-ELT will be built. We are also aware that astronomy can be a great called by the then Chilean Foreign Minister because way to attract children to science. To this end, we there was a serious problem. Chile had donated Thanks to those unique Chilean skies, today I have are working jointly with ESO in the creation of a to ESO a very large piece of land to build the Paranal the opportunity to be part of this ceremony com- national astronomical network open to all citizens. Observatory. In fact, the observatory was already memorating the 50th anniversary of the foundation This is a new step towards making astronomy an being built. But there was a Chilean family claiming of ESO. I am proud to represent the country where essential part of Chile’s track record. This is also this piece of land saying that there had been a all ESO’s astronomical sites are located. By the why we issue so many press releases on this matter ­mistake. The Chilean government commissioned a way, referring to Brian Schmidt’s speech mentioning and encourage people to visit Paranal. tribunal to determine who the legitimate owner of James Bond, some scenes from the recent film that land was and determine its value for the Obser- Quantum of Solace were shot at Paranal. We really appreciate the work you have carried out vatory. in our country and we want people to know that The work carried out by ESO over the last 50 years we are doing things together. To set an example, Both the family and the government agreed to set in the design of structures and the operation of the only a few months ago Chile, Mexico, Colombia and a price for Paranal and I was chosen to determine most important astronomical projects has been Peru signed — in Paranal — the Agreement for the that price. I don’t know why but they chose me to of paramount importance to Chile. We have had an Pacific Alliance. Let me once again extend my decide the price for the Paranal site. Whatever price opportunity of being part of some of the most impor- appreciation to Massimo Tarenghi and the Director I set would have to be the price that the government tant discoveries in astronomy. of the Observatory for their warm hospitality. would pay to the family. Since I was an economist, I had to learn a lot about astronomy. I went to Paranal As you may all know, our country has received and I would like to propose a toast — not to the last to see what they were doing there and I talked with will continue to receive most of the world’s invest- 50 years, but to the coming 50 years. I am sure that many astronomers to find out the price for the site to ment in astronomy. In a few more years, Chile will be the next 50 years will provide us with many more build an observatory. To make a long story short, I home to more than 68 percent of the world’s largest incredible things, new discoveries, not only for Chile finally came to the conclusion that the Chilean skies optical and radio telescopes. ESO will be part of but also fantastic developments for all mankind. were unique. The only competition for Paranal was a the E-ELT, the largest optical telescope, and part of small peak nearby called Armazones. In my final ALMA, the largest radio telescope in the world, both

Closing Remarks the Member States in ESO’s Governing bodies. It is other ministers in your governments, tell your prime now up to the governments of the Member States ministers, tell your heads of state and tell all the citi- Xavier Barcons, President of ESO Council to secure these plans, including the E-ELT pro- zens in your countries: gramme, by applying and extending the principles – that ESO builds and operates the most powerful of cooperation and excellence that have been at astronomical observatories in the world; Dear Ministers, Dignitaries and Guests the root of ESO’s successful 50-year history. I’m fully – how ESO enables astronomical research in your confident that we, all together, will achieve this. country and fosters scientific cooperation with I’m fully confident that you have enjoyed tonight’s ­others; and celebration of the fiftieth anniversary of ESO. The But before you leave, I have one very important – explain to them how ESO promotes R&D in institu- delightful talks by ESO astronomer Nadine Neumayer, request for all of you, and most especially for the tions and industries in your home country. by Nobel Laureate Brian Schmidt and by ESO ministers and authorities that represent ESO’s ­Director General Tim de Zeeuw have surely pro- ­Member States: Be proud of ESO! And now, please join me in wishing a most success- moted a most enjoyable dinner. ful next 50 years to ESO. To ESO! ESO is your achievement. It is part of your R&D sys- I also hope that this night has, in addition, served the tems, which happens to be in the form of an Inter- Thank you very much for your continued support, for purpose of explaining better how ESO works, what governmental Organisation, which has reached far having been here tonight and for being part of the are its main achievements and what are the plans for beyond than which would be conceivable for a single big ESO family. the immediate future of the Organisation. These country. Spread the word and be the proud ambas- plans have been put together by delegations from sadors of ESO. Tell people in your ministries, tell

14 The Messenger 150 – December 2012 M. McCaughrean (ESA)/ESO

Figure 7. The E-ELT prototype mirror segment after signing by the ESO Member State representatives.

The Messenger 150 – December 2012 15 Telescopes and Instrumentation Telescopes STFC/UKATC/ESO

Upper: A view inside the dewar of the K-band Multi Object Spectrometer (KMOS) showing the 24 robotic arms. KMOS is currently being com­ missioned at the Very Large Telescope (VLT) Unit Telescope 1. See Sharples et al., 2010, The ­Messenger, 139, 24 and Announcement ann12071 for more details.

Lower: An aerial view of the VLT platform on Cerro Paranal taken in 2010.

J. L. Dauvergne & G. Hüdepohl/ESO Telescopes and Instrumentation

Growth of Observing Programmes at ESO

1 Number of proposals/Pls Figure 1. Number of Ferdinando Patat 1200 Gaitee Hussain1 ­distinct proposals re­­ Number of proposals ceived by ESO from P20 1000 (1977) to P90 (2012). Number of Pis This is also known as the 1 Is ­Breysacher plot, after ESO 800 ESO astronomer Jaques Breysacher, who pro- oposals/P

pr 600

duced the first version of of There has been a continuous growth the diagram (Breysacher

in applications for ESO telescopes from 400 & Waelkens, 2001). The umber the first calls for proposals in the late N number of distinct princi- pal investigators is also 1960s. Typically one thousand applica­ 200 plotted since P55. The tions are now received per semester peak observed in P84 involving over 3000 astronomers world­ 0 coincides with the start 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 of X-shooter operations. wide. A brief history of the evolution Period of the allocation process is presented and a snapshot of the current proce­ dures is given. #HRSHMBS"Nl(RHM$2.OQNONR@KR Figure 2. The growth  in the number of distinct

 investigators (Co-Is) in Introduction ESO proposals is shown  from the start of VLT operations (P62, October The history of the European Southern (R Observatory (ESO) is marked by steady Nl  1998) to P90 (October S" 2012). growth, from a few small telescopes at 

La Silla in the late 1960s, the expansion CHRSHMB  NE

to 4-metre-class telescopes in the 1970s - and 80s, to the opening of the Very  Large Telescope (VLT) on Paranal in 1998.  Today, on La Silla, ESO operates the MPG/ESO 2.2-metre, the 3.6-metre and                               3.58-metre New Technology Telescope /DQHNC (NTT) with five instruments permanently mounted (two each on the 3.6-metre number of proposals kept growing, even- The distribution of the number of submit- and the NTT). Cerro Paranal is equipped tually stabilising at around 500. The start ted proposals and requested time by with the four VLT Unit Telescopes (UTs), of VLT operations was marked by a rapid site since the beginning of VLT operations the 4.1-metre Visible and Infrared Survey increase, bringing the number of pro- is presented in Figure 3 (left and right Tele­scope for Astronomy (VISTA), the 2.6- posal submissions above ~ 700, followed respectively). Despite the expected de­­ metre VLT Survey Telescope (VST), and by steady growth to today’s ~ 950 pro- crease in demand for observing time at the four 1.8-metre auxiliary telescopes posals per semester, submitted by about La Silla following the reduced number of the VLT Interferometer (VLTI). Each of 700 distinct Principal Investigators (PIs). of telescopes offered at this site and the the UTs features three foci (two Nasmyth The total time request averaged over the increasing instrumentation contingent platforms and one Cassegrain focus), last four years is about 3170 nights per at Paranal, it is still in demand. The time so that up to twelve instruments can be semester (about 65% for Paranal only), of request for La Silla averaged over the last simultaneously offered and easily switched which about 1070 nights are scheduled three years is about 900 nights/semester, during the night. Currently eleven instru- for execution. to be compared with the ~ 1450 nights/ ments are offered for normal operations semester during the first three years of at the VLT and three at the VLTI. ESO The overall observatory pressure (defined VLT operations. The NTT and the 3.6- is also part an international collaboration here as the ratio between the submitted metre telescope remain in high demand, involving the Max-Planck-Institut für and the scheduled time) is ~ 3.0. How- and the tendency is to request the time ­Radioastronomie (MPIfR) and Onsala ever, at some telescopes (and particu- through Large Programmes (LPs; pro- Space Observatory (OSO) for the Atacama larly at some instruments, e.g., FORS2, posals requesting over 100 hours of tele- ­Pathfinder Experiment (APEX) and 25% X-shooter and HARPS), this exceeds 5.0. scope time that can be distributed up of the observing time is allocated to ESO. The increase in the number of investi­ to four consecutive years on La Silla or gators on ESO proposals from the start two consecutive years on Paranal). This The history of the number of proposals of VLT operations is shown in Figure 2, is reflected in the time allocation: in P90 submitted to ESO (per semester [six which presents the evolution of the num- at the 3.6-metre telescope ~ 73% of the months], called a Period) over the last ber of distinct co-investigators (Co-Is). time was allotted to LPs, 18% to Normal 35 years is shown in Figure 1. In the pre- The current number is around 3000 indi- Programmes and 9% to Guaranteed VLT era (i.e., before Period 63 [P63]), the vidual users. Time Observations. With the deployment

The Messenger 150 – December 2012 17 Telescopes and Instrumentation Patat F., Hussain G., Growth of Observing Programmes at ESO

 

/@Q@M@K  /@Q@M@K  +@2HKK@ +@2HKK@  /$7 /$7  /@Q@M@K>+@2HKK@

 /@Q@M@K>+@2HKK@   3NS@K

 MHFGSR  NONR@KR

Q   C SHLD NEO   TLADQ -

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                                                          /DQHNC /DQHNC

Figure 3. Number of proposals (all types) by site (left) 4. Guaranteed Time Observations (GTO): Most of the proposals received are for and number of requested nights (right) plotted as These arise from contractual obliga- Normal Programmes. Typically 15 to 20 a function of time since the beginning of VLT opera- tions. tions of ESO to the consortia who have Large Programme proposals are received built ESO instruments. This time is each semester. The other proposal cate- only accessible to the GTO consortia. gories (ToO and Calibration) only involve of the PESSTO public spectroscopic sur- 5. Calibration: This type of proposal a few percent of the total proposal pool. vey (which has an allocation of 90 nights/ was introduced to allow users to com- year), the NTT is moving towards a very plement the existing calibration of similar configuration. ESO instruments and to fill any gaps Observing modes that might exist in the calibration plan. 6. Director’s Discretionary Time (DDT): Since the beginning of VLT operations, Proposal types Up to 5% of the available general time on ESO telescopes can be requested observing time may be used for DDT either in Visitor Mode (VM) or in Service In parallel with the increased availability proposals in a current period. As Mode (SM). While VM allows the observer and demand for observing time, there has opposed to the other proposal types to take on-the-fly decisions and to make been an evolution in the types of ob­­ described above, DDTs can be sub­ use of non-standard modes, SM enables serving proposals in order to adequately mitted at any time during the semester. the exploitation of the best atmospheric encompass the wide range of science conditions or repeated short visits to the programmes. In the current implementa- A new programme type, dubbed Moni­ same target during a semester. VM is the tion, there are six different types of pro- toring Programmes, is also being imple- classical observing mode, in which the posals: mented. This serves projects requesting observations are carried out by a visiting 1. Normal: Programmes that require small amounts of time (of the order of astronomer selected by the proposing less than 100 hours and span one tens of hours) spanning several periods, team. SM observing runs are executed semester. and is meant to secure continuity to by observatory staff following an estab- 2. Large: Programmes that require more ­programmes aiming at time, for instance, lished priority order. For each telescope than 100 hours and can span one or coverage of slowly varying targets. SM runs are grouped into three queues, more semesters (up to four for Paranal 2DQUHBD,NCDQDPTDRS@KKNB@SHNM Figure 4. Time evolution and up to eight for La Silla). A Large   Programme typically has the potential of the fraction of VLT   requested and sched- to lead to a major advance or break- uled time in SM (upper through in a field and includes a plan   curves) and VM (lower for data reduction and analysis by a curves) since the begin- dedicated team.    ning of VLT operations. K Statistics refer only 3. Target of Opportunity (ToO): Up to S@   to Normal and ToO pro- 5% of the available general observing grammes, excluding MNESN time may be used for ToO proposals.   Large Programmes and Q@BSHN

% GTO proposals. Within this framework it is also possi-   ble to apply for the Rapid Response 1$0l2,   Mode (RRM) implemented at the VLT. 2"'l2, 1$0l5, This mode allows users to trigger   2"'l5, observations with a very fast reaction   time (a few minutes).                             /DQHNC

18 The Messenger 150 – December 2012 which reflect their scientific ranking (see -TLADQNEOQNONR@KRODQ./"B@SDFNQX  Silva, 2001). The rank classes are defined as follows: ! "# Class A: All possible efforts will be made 

to execute all observations  ­corresponding to the runs in the 

requested observing period. ONR@KR QN Class B: These runs will be executed in  the requested observing period NEO

on a best-effort basis. 

Class C: Filler runs. Observations will only -TLADQ be executed if the observing conditions do not permit obser-  vations for runs within classes A and B.               /DQHNC Although the original plan had foreseen a 50/50 distribution between the two Figure 5. Distribution of submitted proposals by sci- composed of the Director for Science, modes, the popularity of SM steadily entific category is shown for the last twelve years the Head of the Observing Programmes (A: Cosmology; B: Galaxies and galactic nuclei; C: increased during the first five years of VLT ISM, star formation and planetary systems; D: Stellar Office (OPO), the former OPC Chair and operations. This is very clearly demon- evolution). two members of notable accomplishment strated by the evolution of the time re­­quest in astronomy. for the two modes (see Figure 4). From an almost equal 50% fraction recorded in OPC members serve for two years the first semester, the share has evolved numbers of proposals which these cate- (four ESO periods), while panel members to the current situation, in which about gories receive each period. Interestingly, serve for one year (two ESO Periods). A 75% of the time is requested in SM. this number has evolved significantly fraction of the panel members are invited Rather than enforcing the original opera- since the beginning of VLT operations, to serve an extended, second one-year tions plan, ESO has followed the demand when the proposals were evenly distrib- term, to ensure sufficient continuity in the from the community. In the current uted across the four categories. The review process. The high turnover en­­ schema SM is not offered for La Silla tel- data covering the last twelve years of sures that, with time, a significant fraction escopes, which are operated in VM only. operations (see Figure 5) clearly show an of the community gains experience in the in­­crease of the number of proposals in process from the inside. category D (stellar evolution) and espe- Observing Programmes Committee and cially C (ISM, star formation and planetary ESO facilitates the OPC process, but Proposal Review systems). The growth in the latter is does not take active part in the scientific related to the expansion of the exoplanet evaluation of the proposals. ESO time Telescope time at ESO is allocated follow- field. allocation is carried out by implementing ing the recommendations of the Ob­­ the OPC recommendations while serving Programmes Committee (OPC). Each panel has six members, including accounting for any technical and sched- It is the function of the OPC to review, one panel Chair and one co-Chair. Apart uling constraints. A full description of evaluate and rank all the proposals sub- from the individual panels, the advisory the OPC process and an overview of the mitted in response to the call on scientific committee, the OPC, is composed of the software scheduling tools used by OPO merit. From this review process, the 13 panel Chairs, three panel co-Chairs to facilitate the allocation of OPC priori- ­committee advises the Director General (one in category A, two in B), and the tised proposals on the telescopes can be (DG) on the distribution of observing time, OPC Chair, who is not a panel member. found in Patat & Hussain (2012). taking into account ESO’s scientific pol- This corresponds to a total of 17 OPC icy. The OPC includes 13 panels to cover members, and with 72 panel members, a the four science categories: total of 89 scientists. Director’s Discretionary Time A: Cosmology (three panels); B: Galaxies and galactic nuclei (two The OPC and panel members are DDT proposals can be submitted any ­panels); selected on the basis of their scientific time. A DDT proposal must necessarily C: Interstellar medium (ISM), star forma- competence. During the selection, some belong to one of the following categories: tion and planetary systems (four allowance is made for gender balance − proposals of ToO nature requiring the p­anels); and for distribution across ESO member immediate observation of a sudden and D: Stellar evolution (four panels). states, but these aspects are not rigidly unexpected astronomical event; enforced. The candidates are proposed − proposals requesting observations on a The varying number of panels within by the OPC Nominating Committee. topical and highly competitive scientific each category is due to the different This board is advisory to the DG and is issue;

The Messenger 150 – December 2012 19 Telescopes and Instrumentation Patat F., Hussain G., Growth of Observing Programmes at ESO

− proposals seeking follow-up observa- out in Service Mode, they are normally a full adoption of the Paranal schema that tions of a programme recently con- considered for Paranal telescopes only. is operational at that time. This includes ducted from ground-based and/or Successful DDT applicants are asked to time allocation with the E-ELT considered space facilities, where rapid implemen- submit a report within four weeks from as another telescope of the observatory. tation should provide breakthrough the completion of the observations. With more than a decade before first light results; for the E-ELT, there is ample time to dis- − proposals of a somewhat risky nature, cuss and debate with the community the requesting a small amount of observ- Perspectives most appropriate methodology and phi- ing time to test the feasibility of a pro- losophy for the time allocation. The pro- gramme. As is apparent from this overview, the cess of consul­tation will start soon after ESO allocation and scheduling process the start of construction. The DDT proposals are reviewed by an has evolved to accommodate the vary- ESO internal standing board, the DDT ing needs of its community and to ensure Committee (DDTC), which is chaired by the optimal use of observing time on Acknowledgements the Head of OPO and includes ESO all the telescopes. The present system is The authors are grateful to Gautier Mathys, former ­Faculty astronomers, the Director for Sci- not without its weak points and the fol- head of the OPO, for his fundamental input on the ence and the VLT Programme Scientist. lowing article (Brinks et al., p. 21) summa- time allocation procedures and policies. The DDTC is advisory to the DG, who rises the findings of the OPC working takes the final decision based on a group that recently reported (Brinks & References ­recommendation prepared by the Chair. Leibundgut, 2012). OPO is also studying Further details of the allocation process the implementation of a new proposal Breysacher, J. & Waelkens, C. 2001, in Organizations are presented in Patat & Hussain (2012). submission system, which will feature a and Strategies in Astronomy — Vol.2 (OSA2), ed. more integrated and user-friendly ap­­ A. Heck, Kluwer, 149 Brinks, E. & Leibundgut, B. 2012, OPC Working Typically 50 to 60 DDT proposals are proach. On a longer term and in view of Group Report. ESO received per semester (at an average rate the forthcoming E-ELT era, ESO is also Patat, F. & Hussain, G. A. J. 2012, in Organizations of two per week), with requests that range considering a more ­radical evolution People and Strategies in Astronomy — Vol. 2 from tens of minutes to a few hours. to the next generation system. The oper- (OPSA2), ed. A. Heck, in press Silva, D. 2001, The Messenger, 105, 18 Since DDT proposals can only be carried ational scenario for the E-ELT is based on ESO/S. Brunier Brunier ESO/S.

360 degree view of the sky from Paranal showing the disc of the Milky Way extending across the sky. See Picture of the Week 11 June 2012 for an explanation.

20 The Messenger 150 – December 2012 Telescopes and Instrumentation

Report of the ESO OPC Working Group

Elias Brinks1 arily follows the scientific recommenda- The members of the working group were Bruno Leibundgut2 tions of the OPC and its panels. Very Jacqueline Bergeron (IAP, France), Gautier Mathys2, 3 few official complaints, less than half a Elias Brinks (Chair, University of Hertford- dozen, are lodged per semester once shire, UK), Fernando Comerón (ESO), the outcome is made public, which is a Simon Garrington (Jodrell Bank Observa- 1 Centre for Astrophysics, University of testament to the dedication of the panel tory, UK), Bruno Leibundgut (ESO), Hertfordshire, UK and OPC members and to the general ­Gautier Mathys (ESO, now at the Joint 2 ESO acceptance of the process by the com- ALMA Observatory), Michael R. Merrifield 3 Joint ALMA Observatory, Chile munity. ­(University of Nottingham, UK), I. Neill Reid (Space Telescope­ Science Institute, The large number of proposals has started USA) and Letizia Stanghellini (National With over 1000 proposals per semester to make the review process increasingly Optical Astronomy Observatory [NOAO], for ESO telescopes, the community onerous, both for astronomers serving on USA). The OPC-WG was charged to is facing the problem of fair and robust the OPC and its panels, as well as for examine the current processes and pre- selection of observing programmes. the Observing Programmes Office (OPO). sent ­recommendations for improvements. We report here on a working group to At the current level of proposals, 13 pan- investigate the current selection pro­ els with six members each are needed in cess and procedures and identify pos­ order to review the proposals and keep The current OPC process sible improvements. The working group the number of proposals per panel mem- report summarises the current process, ber to a manageable limit. The time spent The ESO process to rank proposals for based on peer review, that has been by panel members refereeing proposals, telescope time is similar in philosophy to in use for many years at ESO and other plus the time involved in the face-to-face that employed at several other ground- comparable ground- and space-based meeting, represents a considerable in- based (e.g., NOAO) and space-based observatories, and presents an inven­ kind contribution. The current work load (e.g., Hubble Space Telescope [HST] and tory of the changes and approaches on panel and OPC members is very high Spitzer) observatories. There are several that may be considered to make the pro­ and any further increase in the number proposal categories: Normal, Large, cess more manageable and less time- of proposals will stress the current review Guaranteed Time (GTO), Calibration and consuming, while at the same time pre­ process even more. Target of Opportunity (ToO). The cate- serving its integrity. The working group gory of short proposals has been discon- presented several recommendations, The situation is exacerbated by the sub- tinued (see below). Director’s Discre­ which have been discussed with ESO stantial oversubscription rates of three tionary Time (DDT) proposals are handled committees and analysed by the opera­ to five (see Patat & Hussain, p. 17). Once in a separate process and were not dis- tional groups at ESO. applications on a telescope/instrument cussed by the working group. For defini- combination reach a tipping point, many tions of these categories the reader is good proposals will not make it to the referred to the ESO web pages1 or one of Introduction: Identification of the problem ­telescope. As there is nothing fundamen- the recent ESO Calls for Proposals. The tally wrong with those proposals, their process is divided into Phase 1 (pro- Over the past two decades, the number Principal Investigator (PI) will likely resub- posal) and Phase 2 (detailed scheduling of proposals submitted every six months mit them with minor changes, adding to preparation). Technical feasibility is to ESO has been increasing almost line- the already substantial oversubscription. judged after Phase 1 and before Phase 2. arly, reaching over 1000 proposals for The large over­subscription leads to frus- the first time in 2009, followed by a slight trated users, as good proposals are not On average a panel deals with 70–80 decrease over the past three semesters. allocated time. Similarly, serving as a proposals, to be reviewed usually within This large volume of proposals is due to a panel member can become an exasper- four weeks. Within each panel, all mem- combination of additional ESO Member ating experience as many good propos- bers are required to assign a pre-OPC States joining, an increase in the number als end up being marked as not good grade to each of the proposals. Each of active astronomers and the many facili- enough to be scheduled. Even when pro- panel member is first referee on 12–15 ties on offer. The increase is correlated posals are basically fine and nothing proposals which (s)he will need to pre- with the number of Principal Investigators much can be mentioned to improve sent in the panel meeting and for which (PIs). For a description of the current them, users expect to receive feedback. a comment will have to be provided after Observing Programmes Committee (OPC) the meeting. process see the accompanying article by In a sense, ESO is in danger of becoming Patat & Hussain (p. 17). the victim of its own success. Although ESO applies a triage based on the pre- OPO can still manage the number of pro- OPC grades, i.e., the lowest 30% of the The process employed by ESO to select posals submitted in each semester, it is ranked proposals on the basis of the the best projects and award time on one causing a workload that is becoming ­pre-OPC grades are eliminated from dis- of its telescopes is a classical peer review increasingly demanding for OPC panel cussion at the meeting. Panel members system. The ESO Director General (DG) members. This was the reason for setting can still request to discuss a triaged allocates the observing time and custom- up the OPC Working Group (OPC-WG). ­proposal, if they think it merits it. Figure 1

The Messenger 150 – December 2012 21 Telescopes and Instrumentation Brinks E. et al., Report on the ESO OPC Working Group

  set of proposals. The author concludes that the results of the two independent   panels are correlated, but with a consid- erable random variation. There was no   perceptible decrease in this variation near the top or bottom end of the distribution   (see also the example in Figure 2).   RRHFMDCFQ@CD Clearly, it is important for this or similar LDDSHMFFQ@CD R RBGDCTKDC   tests of the classical peer review process RBGDCTKDC to be performed in order to quantify its /NRSl   RBGDCTKDC reproducibility. The working group sug- SQH@FDC gested that ESO could use the fact that   SQH@FDC each scientific category has several panels SQH@FDC to test the reproducibility of the rankings   SQH@FDC by submitting a subset of the proposals to                   /QDlLDDSHMFFQ@CDR more than one panel. This would be done “blind” for the panel members and would Figure 1. To illustrate the effect that triage has on the illustrate triage at the 30%, 40%, 65% and 80% therefore provide ESO with a means to selection process, the grades from before and after level. At a 30% triage threshold, it is unlikely that any measure to what extent the results are the panel meetings are shown for the proposals for triaged proposal would have been unfairly excluded ESO Period 86. The three horizontal lines show the from the panel discussion. Proposals with a post- reproducible. The additional workload per top 10%, 15% and 25% of the final ranking (lower meeting grade of 5.0 were rejected; they include referee was considered to be tolerable. grades are assigned to better proposals) and are those that were triaged based on their pre-meetings indicative of the oversubscription. The vertical lines grade, which did not qualify for scheduling. Evolutionary changes shows a comparison of the effect of the trust of the community. In a report on ­triage for proposals from Period 86 with peer review by the Royal Society (1995) it The basic criteria for a better system grades before and after the panel meet- is stated that: are fairly straightforward: an ideal system ings. All other (viz. non-triaged) proposals “Peer review is to the running of the sci­ produces a better quality outcome at a are discussed during the panel meetings. entific enterprise what democracy is to lower cost in terms of community invest- Figure 2 shows plots of the grade and the running of the country. It may not be ment. Many evolutionary changes were rank of proposals from Period 86, Panel the most efficient system but it is the considered: to the way the review panels B2 (Galaxies and galactic nuclei: Unre- least susceptible to corruption. The con­ work, to the frequency at which the review solved and resolved stellar populations) cept of peer review, in spite of all its dif­ is carried out, and to ways to restrict the both pre-OPC and after panel discussion, ficulties, retains the confidence of most number of proposals. In its deliberations, showing generally good agreement, with working scientists.” the OPC-WG was guided by the principle a significant narrowing of the dispersion that for any proposed change, the pro- following the panel meeting. Scheduling As mentioned, peer review enjoys the cess should: is based on the grades assigned through trust of the community. Those with expe- 1. be driven by scientific excellence; the panel discussions. The OPC proper rience of peer review, either as member 2. be fair (as perceived by the community); mostly focuses on the discussion of LPs of a time allocation committee or as PI or 3. be robust against conflicts of interest; and a sub-panel of the OPC deals with Co-I of a proposal, will gladly admit that 4. be robust against abuse/cheating; the ToO requests based on the grades there is a measure of randomness in the 5. preserve confidentiality; given by the panels. process. There is a consensus, largely 6. result in an acceptable/manageable unsubstantiated (see Figure 2), that the workload for the community; Large proposals (LPs) are discussed in process is repeatable for the top 10–20% 7. provide useful feedback; joint panels, i.e., within the four broad of proposals. In other words, the really 8. be adaptable to changing circum- ­science categories. A digest of this dis- outstanding proposals are recognised. stances; cussion and recommendation is fed to the Similarly, it is argued that there is broad 9. be as manageable for ESO as the cur- OPC, which in turn votes which LPs are agreement on the bottom quartile. Implicit rent system. accepted. Calibration proposals are few in this view is that, for all remaining pro- and are only discussed in the OPC. See posals, the outcome is determined more The OPC-WG recommended a rationali- Patat & Hussain, p. 17 for more details. by external circumstances than by intrin- sation of the large variety of proposal sic merit of the proposal. types. The OPC-WG supports the combi- nation of the application forms for Normal Validity of peer review The WG has found just one paper, by and Short proposals and restricting the Hodgson (1997, and references therein), length of the scientific justification to one Peer review has become the gold stand- that comes closest to a situation where page. This has already been implemented ard for ranking proposals. It clearly has two independent panels ranked the same from Period 87 (2010).

22 The Messenger 150 – December 2012 /QDlLDDSHMFFQ@CDR@MCRS@MC@QCCDUH@SHNMR /NRSlLDDSHMFFQ@CDR@MCRS@MC@QCCDUH@SHNMR     &Q@CD 2SC#DU &Q@CD 2SC#DU               &Q@CD &Q@CD        

   

                       1@MJ 1@MJ

Figure 2. Average grade and standard deviation oversubscription rate) and quite a few proposal unattainable and, if the OPC against run rank is shown based on the preliminary exploit the right ascension overlap re­­ knew this, could result in the proposal (left) and final (right) grades of the members of Panel B2 in Period 86. gions between semesters. No obvious being downgraded. detrimental impact on the science is expected. Among the many changes considered, Revolutionary changes only those where the advantages A reduction in the number of submitted clearly outweigh the disadvantages are proposals could also be achieved through The working group considered funda- presented here. A first suggestion was the creation of a new category of moni- mental changes to the classical peer to split the selection according to tele- toring proposals. These are for projects review system with potentially major scope or groups of telescopes. For ex­­ which in any given period lay only a lim- effects for the community or ESO. ample, one could imagine a review pro- ited claim on telescope resources, but cess exclusively for the VLT Unit Tele- run for many periods, if not years, and One could imagine setting a substantial scopes (UTs) on Paranal (including VLTI), therefore guarantee the success of long- lower limit on the number of hours or and others for the 4-metre telescopes term monitoring campaigns. The total nights per semester for a proposal to be on La Silla, and a separate one for the time would in general be less than for considered. This would force the com- Atacama Pathfinder Experiment (APEX). LPs and the number of semesters might munity to form consortia and, depending Few projects request the use of tele- go beyond the LP limit. Because LPs on the lower limit set, would result in scopes on more than one site and the and monitoring proposals are less time fewer proposals. There would then be no large majority are for Paranal (see Patat critical, they could be discussed in alter- need for panels, the decision process & Hussain, p. 17), and hence there is nating periods. The proposed change being limited to the OPC. This would seri- not much to be gained with such a pro- would thus be to schedule LPs, monitor- ously reduce the workload. Also, pro­ cedure. ing proposals, and proposals for La Silla posals would likely attack “big questions” on a yearly basis, the LPs for example and propose coherent work packages. To decrease the load one could increase in even-numbered periods, the other two In such a scenario ESO would be out- the panel size. To avoid even larger OPC sets in the odd-numbered periods. sourcing a large fraction of the decision-­ meetings and contain the costs, one making process to the community. The could imagine a system in which only half The WG also looked into how the number OPC-WG saw many disadvantages to the panel members were assigned as of proposals submitted could be influ- such an approach: ­primary referees and participated in the enced. One way of doing this is to base 1. Powerful individuals or groups could meeting while the other half provided only future allocations on past performance. It monopolise certain areas. written comments and pre-OPC grades. should be remembered that there might 2. Instead of the decision on the merit A clear drawback is that this would be a good reason why data are not of a proposal being taken in a non-­ require more or less doubling the number ­published (e.g., lack of adequate data, partisan way by referees who have no of referees. disappointing result, rejection by a jour- conflict of interest, decisions are nal, etc.). Sometimes at the Phase 2 ­effectively devolved to the consortia. Changing the frequency of OPC meet- stage, PIs realise that their original time Depending on how a consortium is ings was also discussed. A one-year estimate was wrong (usually too low and organised and decisions taken, cycle would not result in a doubling of the frequently due to underestimating the ­excellent science might lose out. number of proposals, but rather result time required for overheads). This then 3. Small time requests for prime science in an increase estimated at approximately forces them to either reduce the time on will not be eligible unless repackaged 30%, because many proposals are re­­ target or reduce the number of targets. as part of a larger application by a submissions (as a result of the substantial This could render the original goals of the consortium.

The Messenger 150 – December 2012 23 Telescopes and Instrumentation Brinks E. et al., Report on the ESO OPC Working Group

4. Unique and singular objects (e.g., once a year, e.g., during odd-­ request, this implies that either fewer Galactic Centre, SN 1987A, etc.) will be numbered Periods; targets are observed, or that less time at a disadvantage. – Review La Silla proposals only once is spent per target. Either of these a year, also in odd-numbered Periods; outcomes could cause a panel to give Several observatories have opted for this – Limit the Call for Proposals for Large a highly ranked proposal a lower grade, mode of operation, usually for a substan- Proposals to once per year as well, which would mean that it should not tial fraction of available observing time. for even-numbered Periods. have been scheduled in the first place. Examples are e-MERLIN Legacy pro- – A more substantial change would be to The WG recommends that if the time jects, Herschel Open Time Key projects, change the frequency of the Call for requests differ by more than what can James Clerk Maxwell Telescope (JCMT) Proposals to once per year. Although be considered reasonable (to be judged Legacy proposals, Hubble Space Tele- the number of proposals will likely alongside the technical feasibility), the scope (HST) Legacy and Treasury propos- increase, it will not double. The reduc- proposal should not be scheduled. als, Spitzer Legacy proposals and pro- tion in agility could, in cases where – Discussion on how the E-ELT can be posals for future instruments like ASKAP this is justified, be made up for by DDT. implemented in the ESO proposal and MeerKAT, at least for the initial years – Most other considered changes, either selection process was limited. The of their operation. To some extent ESO in the way panels deal with the pro­ E-ELT will likely match or exceed the has followed a similar route by imple- posals, or by attempting to limit the oversubscription rate of the most popu- menting public surveys on the survey tel- number of proposals, carry disadvan- lar VLT UT. E-ELT proposals could escopes VISTA and the VST, and more tages that outweigh their advantages. ­simply be accommodated within the recently also at the New Technology Tel- – Peer review is broadly supported by the existing process provided that the sci- ecope (NTT; PESSTO) and with the Gaia– community. There is a preconception ence policies for the E-ELT and other ESO survey with UVES and FLAMES that top proposals will be recognised ESO facilities remain aligned. Alterna- on UT2. ESO might consider extending with little dispersion in their grades or tively the E-ELT could be made avail­ such surveys with La Silla and Paranal ranking. Likewise with poor proposals. able to consortia only, setting a lower telescopes when the European Extremely In other words, peer review is thought limit to the number of nights that can be Large Telescope (E-ELT) is built. It was to deliver reproducible results. It is bid for and letting the community not clear to the OPC-WG how much accepted that the grades or ranking of organise themselves into larger collabo- is gained by having a mix of these mega- all remaining proposals is less clear rations. In the opinion of the WG not requests and normal proposals. cut and that some considerable disper- all telescope time should be allocated in sion might be expected. The OPC-WG that way as there is a risk that the field A radical departure from classical peer tried to confirm this picture but came becomes dominated by a small number review is the method of distributed peer to recognise that precious little in terms of PIs, blocking access to individuals review as described by Merrifield & Saari of data exists that underpins the validity or small groups who, for whatever rea- (2009). For reasons inherent to that of this model of peer review. If anything, son, lack access to these larger con- method, it is not possible to extract what the few tests available to the WG sortia. Also, small projects, in terms of result distributed peer review would showed that a large dispersion exists telescope time, with a potentially high have produced, or how well it compares even for proposals in the top and bot- impact would never be scheduled with classical peer review, by analysing tom quartiles. on their own merit but would have to be the outcome of the latter. In order to do – The WG recommends that the repro- incorporated within a larger time a proper assessment, a full trial would ducibility of peer review is further inves- request. need to be designed. tigated. One method that was sug- – The OPC-WG ran a test with the gested would be that some 10% of the ­dis­tributed review method proposed proposals in any Category (A, B, C by Merrifield and Saari. The test was OPC Working Group conclusions and D), be seen by more than one panel. useful in pointing out several issues that For those proposals that are seen by the user community would probably The conclusions of the OPC-WG are as two panels, it is decided in advance raise if it were to be introduced. Most follows: which grade will be taken for the final obviously, the user community would − There are small changes that can be ranking. This would be done “blind” for need to be thoroughly educated about applied to the current system that the panel members and would there- this method. Also, sufficient trust would would reduce the workload without fore provide ESO with a means to need to be built up before this, or any affecting in any major way the widely measure to what extent the results are other revolutionary approach, will be accepted peer review method. These reproducible. accepted. The OPC-WG encourages are: – The WG is concerned about the fact ESO to perform a larger scale experi- – Implement a new category of moni- that there are substantial differences ment, more closely linked to the ob­­ toring proposals; these proposals between the Phase 1 and Phase 2 time serving proposal process, to explore can be long-term, but ask for modest requests. Although the amount of time distributed peer review as an alternative amounts of time per semester. Open on the telescope in the end is broadly method. up the Call for this type of proposal compatible with that of the Phase 1

24 The Messenger 150 – December 2012 Given the current paucity of data on the did not like the idea of a parallel evalu­ation due course. In the mean time, the num- effectiveness of peer review, the chang- of some proposals to establish the ber of proposals has been decreasing ing landscape, and the unpredictable validity of the peer review process. The over the past few periods to currently effects of alterations to such a complex position by ESO that the proposal selec- about 900 proposals per semester. This process, it is important to recognise­ that tion process should not be used for has the positive effect that the load on this report cannot represent a final con- a “social experiment” to investigate the the OPC and its panels has decreased clusion on the right way forward. effectiveness of peer review was sup- (by about 10%). ported by the OPC as well. The ESO database should allow an investigation The OPC-WG suggested that it would be Follow-up into this question post facto and ESO beneficial to re-visit the proposal selec- should analyse the available data. The tion process regularly, perhaps every The report by the working group was evaluation of the LPs is done in all sub- few years. The composition of the OPC- presented to the OPC, the Scientific panels in parallel and this could be used WG was originally chosen to combine Technical Committee (STC) and the Users as a (limited) dataset for such an investi- the expertise residing within several inter- Committee (UC). There was general sup- gation. The OPC requested that no national observatories with high pro- port for the introduction of monitoring panel member should be asked to referee posal pressures. The exchanges within programmes and ESO has started devel- more than 70 proposals in a given selec- the OPC-WG were very informative and oping this type of observing programme tion round. allowed the members to have a fresh to begin in Period 92. The OPC dis- look at the processes involved in select- cussed whether ESO should move to a The OPC-WG was already very sceptical ing the best science for a given facility. one-year cycle for LPs and proposals for about forcing the community into large ALMA has just finished the proposal La Silla. There was a small majority for collaborations to reduce the number of selection for Cycle 1 and already is deal- a one-year cycle for La Silla proposals, submitted proposals. The ESO commit- ing with more than 1000 proposals per but clear discomfort about evaluating LPs tees (OPC, STC and UC) concurred with cycle. Other observatories are faced with only once per year. The UC also recom- this assessment and this will not be this problem as well and all working mended ESO to stay with the half-yearly regarded beyond the current scheme of group members were interested in return- cadence for proposal submissions of all Public Surveys. ESO has implemented ing to these questions in a few years. telescopes and types. ESO will hence these surveys to make optimal use of the not change the frequency of calls for ob­­ two survey telescopes and also to allow serving proposals. the community to establish a leading References ­ position in a specific subfield. The recent Hodgson, C. 1997, Journal of Clinical Epidemiology, The ESO operations groups evaluated workshop on surveys (see the report 50, 1189 the impact of a move to a one-year cycle by Rejkuba & Arnaboldi, p. 67) has dem- Merrifield, M. R. & Saari, D. G. 2009, Astron & for all proposals in the current operation onstrated the success of this approach. Geophys, 50, 4.16 (arXiv:0906.1943) setup. They concluded that within the Such surveys are followed by a special Patat, F. & Hussain, G. A. J. 2012, in Organizations People and Strategies in Astronomy — Vol. 2 current support scheme a significant review panel to guarantee that the large (OPSA2), ed. A. Heck, in press increase in effort would be needed. The investment of observing time results Royal Society, 1995, Peer Review — An assessment work load would very strongly peak in a corresponding return to the commu- of recent developments. around the scheduling and Phase 2 as nity. ESO and its community will need more proposals would have to be pro- to assess in a few years the balance Links cessed within the same time span to pro- between regular proposals, requesting a vide a full schedule at the beginning of few nights, compared to surveys, with 1 ESO telescope time allocation: the period. The impact for the execution hundreds of nights. The OPC-WG will http://www.eso.org/sci/observing/teles-alloc.html of the observations is not as significant, have a role in this assessment as well. but the cycle between proposal submis- sion and data delivery could increase to Changes between Phase 1 and Phase 2 more than one year, which was consid- for a given proposal will be handled ered by the OPC-WG and the OPC itself more strictly in the future. The proce- as a possible disadvantage. Offsetting dures are available and will be enforced. these delays for scientific programmes by There is a clear imbalance between an increased Director’s Discretionary the numbers of proposals in the different Time allocation was not considered suffi- scientific subcategories. A measure to cient. For the time being no change better distribute the load between the dif- regarding the ESO periods is planned. ferent panels is to redefine the subcate- gories, with the goal of reaching a more The OPC was strongly opposed to even distribution across the OPC panels. ­adding to the work load by increasing the This investigation has started and will evaluation of proposals. In particular, it be presented to the ESO committees in

The Messenger 150 – December 2012 25 Telescopes and Instrumentation

Holographic Imaging: A Versatile Tool for High Angular Resolution Imaging

Rainer Schödel1 also limited: the change of the incoming measure of the image quality and is Julien H. Girard2 wavefront as a function of the line of defined as the ratio between the peak sight leads to a rapid deterioration in the pixel in the normalised PSF and its theo- image quality at distances from the retical maximum value. It is 100% for 1 Instituto Astrofisica de Andalucia (CSIC), guide star larger than the isoplanatic a perfect image and ~ 1% for a seeing- Granada, Spain angle (nominally around 15 arcseconds limited image. Since turbulence is a 2 ESO at 2.2 μm, the K-band). These anisopla- ­statistical process, higher Strehl ratios natic effects can be partially compen- can be reached by selecting only the sated for by the use of multi-conjugated frames with the most compact, high Speckle holography can be used to AO (MCAO) systems and the use of multi- ­signal-to-noise PSFs. In recent years, this re­construct high angular resolution ple (laser) guide stars, but at great cost technique, termed lucky imaging, has images from long series of short expo­ in instrumental as well as operational become popular at optical wavelengths, sures if the point spread function (PSF) complexity. In addition to, and independ- where AO is still challenging. Lucky from each frame can be measured reli­ ent of, these effects, various technical ­imaging suffers, however, from large ably. We show that through use of multi­ limitations make it difficult to calibrate the overheads because typically a large frac- ple reference stars and iterative PSF AO PSF (­Sivaramakrishnan et al., 2003; tion of the data (frequently > 90%) subtraction, we can obtain highly accu­ Lacour et al., 2011). Here, we show that must be discarded in the process. Since rate PSFs. The technique is optimised holography can in many situations offer the number of speckles increases ap­­ for crowded fields and results in images an attractive alternative to AO. It leads to proximately with the square of the tele- with excellent cosmetics and high Strehl high quality images, works with very faint scope aperture, lucky imaging becomes ratio from the optical to the mid-infrared (infrared) reference stars, and can com- extremely inefficient for telescopes with regimes. With examples from NACO, pensate anisoplanatic effects in crowded apertures of more than a few metres. VISIR, and HAWK-I we show that holo­ fields. Details on the experiments de­­ graphy opens up novel and unforeseen scribed here, as well as more analysis possibilities and can be an attractive and discussion can be found in Schödel Holography alternative to adaptive optics. et al. (2012). A more complex, but more efficient, ­algorithm than SSA is speckle hologra- In the past decade adaptive optics (AO) Speckle imaging phy, which makes use of the informa- assisted observations have become the tion and flux content of the entire speckle standard for obtaining images near the Before the maturity of AO, speckle imag- cloud of each frame, not just of the diffraction limit of large ground-based tel- ing was widely used to obtain diffraction- brightest speckle. This results in higher escopes. At the ESO Very Large Tele- limited images. It played, for example, a Strehl ratios and sensitivity. Efficiency is scope (VLT), the AO-assisted near-infrared key role in determining the proper motions boosted because frame selection be­­ (NIR) camera NAOS/CONICA (NACO) and orbits of stars near the massive black comes (largely) unnecessary. Holography has been in operation since 2002 with hole at the centre of the Milky Way, Sagit- allows one to reconstruct the best esti- spectacular success (see e.g., Lenzen et tarius A* (e.g., Eckart & Genzel, 1996). mate (in the least squares sense) of the al., 2003; Rousset et al., 2003; Girard Speckle imaging is based on recording astronomical object’s Fourier transform: 2 et al., 2010). Its AO capability can im­­ series of hundreds or thousands of O = /<|Pm| > where O, Im and Pm prove the angular resolution in the NIR images with exposure times around 0.1 are the Fourier transforms of the astro- (viz. 1–5 µm), which is typically limited by seconds. In these frames stars appear as nomical object, of the m-th frame of the atmospheric turbulence, from the seeing, interference patterns or speckle clouds observed image and its instantaneous in the range 0.3–2.0 arcseconds, to (see Figure 1, left). Image reconstruction PSF, respectively (Primot et al., 1990). 0.03–0.15 arcseconds depending on the is performed a posteriori, for example The brackets denote the mean over the wavelength. with the simple shift-and-add (SSA) algo- total number of frames and the asterisk rithm: a different shift is applied to each the complex conjugate. The final recon- Despite its immense advantages, AO is frame so that the brightest speckle of the structed image is obtained after multipli- not a universal solution to the problem reference star always comes to lie at the cation of O with the telescope transfer of diffraction-limited imaging through the reference pixel. Finally, the shifted frames function (TTF), followed by an inverse Earth’s atmosphere. AO systems need are averaged. The PSF of the recon- Fourier transform. The TTF is usually an either a bright natural guide star, which structed image (Figure 1, middle) appears Airy function. The main difficulty in the seriously limits sky coverage, or a laser like a diffraction-limited core superposed application of holography lies in obtaining guide star (LGS), which entails some on a broad seeing halo. reliable estimates of the Pm. In the ideal additional image degradation because of case, the field contains a single, bright, the cone effect (i.e. the finite distance SSA was widely used because it is isolated reference star, whose speckle of the LGS reference from the source) easy to implement, fast and robust. How- cloud can be used to estimate the Pm, and tip-tilt anisoplanatism (elongation of ever, the achieved Strehl ratio is typically similar to the role of the guide star in AO. the PSF when the faint tip-tilt star is off- only around 10% in the K-band with an This situation is, however, very rare axis). The field of view (FoV) with AO is 8-metre telescope. The Strehl (ratio) is a and can be dealt with efficiently by AO.

26 The Messenger 150 – December 2012 Figure 1. Speckle ­imaging of the Galactic    Centre with NACO. Left: Individual short    exposure. Middle: Sim-    ple shift and add (SSA) ǥ ǥ ǥ    reconstruction. Right:    Holographic reconstruc- #DB #DB #DB tion. The 11 reference l l l stars have 7 ≤ Ks ≤ 10 mag and are marked by l l l circles in the left panel.

   l l    l l    l l 1 ǥ 1 ǥ 1 ǥ

Therefore holography has rarely been DIMM seeing ~ 0.5 arcseconds, coher- Sensitivity is, however, one aspect where used in practice. ence time τ0 = 2–3 ms). Figure­ 1 shows a AO clearly wins out over holography, speckle frame as well as an SSA and a where it is fundamentally limited by the Here we present a novel, game-changing holographic image reconstruction. While readout noise of the detector electronics. approach that allows us to use hologra- the Strehl of the SSA image is only ~ 9%, The point source detection limit is about phy even with faint guide stars in ex­­ the holographic image has a Strehl of 1.5 magnitudes deeper in the AO image tremely crowded fields. It is based on: ~ 82% and also excellent PSF cosmetics. (Ks ~ 20.5) than in the holography image (a) iterative improvement of the PSF; and (Ks ~ 19). This cannot be seen in Figure 2 (b) the (optional) use of multiple reference because the region shown is completely stars. Relative fluxes and positions of High quality images dominated by crowding. However, due to stars in the observed field can initially be the high PSF quality, holography can de­­ obtained from an SSA image (or from a A comparison between AO and holo- liver smaller astrometric and photometric previous holographic reconstruction). graphic imaging of a small region around uncertainties on bright sources than AO. Subsequently, preliminary PSF estimates Sagittarius A* is shown in Figure 2. Ide- can be obtained for each frame from the ally, the comparison has to be done Although holography is closely related to median superposition of multiple refer- between contemporary data taken under deconvolution techniques like Wiener ence stars, whose relative positions are similar conditions. In the absence of such ­filtering or Lucy–Richardson deconvolu- now known with sub-pixel precision. data, we try to stay on the conservative tion, it does not suffer the typical prob- Then, the preliminary PSFs can be used side and use one of the highest quality lems of those methods, like ringing, pho- to subtract all secondary sources near NACO GC datasets ever taken (31 March tometric biases, difficulties in dealing the reference stars that were detected in 2009, DIMM seeing ≤ 0.5 arcseconds, with ex­­tended emission, or creation of the SSA image. Finally, high accuracy τ0 ≈ 47 ms). The comparison underlines spurious sources. Holography is an en­­ ­values of Pm are obtained from a median the extraordinary image quality obtained tirely linear process, leads to well-behaved superposition of the reference sources with the holography technique. In addi- noise properties in the reconstructed from the cleaned frames. tion, also in Figure 2, we show a holo- images, and provides reliable photometry. graphic image reconstruction that has We use speckle data of the Galactic been obtained by using only the faintest ­Centre (GC) obtained with NACO’s cube stars (Ks ~ 13) as reference stars. Those A highly flexible technique mode on 7 August 2011 to demon- stars are barely visible in the individual strate the effectiveness of this algorithm frames. Nevertheless, a high Strehl As we have shown above, holographic (Ks-band, S27 camera, 12 500 frames, (~ 45%) could be obtained by using a imaging works with rather faint reference Detector Integration Time [DIT] = 0.15 s, large number of them (24 in this case). stars. Moreover, an arbitrary number of

Figure 2. Comparison       of speckle holography and AO. Left: AO image of the immediate envi-       ronment of Sagittarius    ǥ ǥ ǥ A*. Middle: Image recon-          structed from speckle #DB #DB #DB data via the holography l  l  l  technique, using ten ­reference stars of 7 ≤ Ks ≤ 11. Right: Holo- l  l  l  graphic reconstruction using 24 Ks ~ 13 refer-       l  l        l  l        l  l  ence stars. 1 ǥ 1 ǥ 1 ǥ

The Messenger 150 – December 2012 27 Telescopes and Instrumentation Schödel R., Girard J. H., Holographic Imaging: A Versatile Tool

them can be combined, a possibility that The short integration times necessary for Although, for technical reasons, we only lies beyond the capabilities of current speckle imaging can make it necessary show a small field in Figure 4, we note AO systems. Therefore, holography can to window NACO’s detector to 512 × 514 that the FoV of HAWK-I with the exposure free us from many constraints imposed pixels. Longer DITs are desirable in order time used (DIT = 0.2 secsonds) is 2048 by classical, single conjugate AO. Holo­ to use the full detector array. This was × 512 pixels, or roughly 3.25 arcminutes graphy is thus naturally suited to imaging tested using DITs of 0.4 seconds (>> 10 squared. We believe that even longer highly embedded fields, for example in times longer than the atmospheric coher- integration times and thus larger FoVs, up the Galactic Bulge or near the Galactic ence time). The diffraction limit was to 2048 × 1024 pixels (~ 6.5 arcminutes Centre, that have so far never been pos- reached, albeit at low Strehl (~ 10%). squared) are feasible. We note that stars sible to observe at high angular resolution as faint as K ~ 16 can be identified on from the ground because of the absence the speckle frames. Since the density of of suitable natural guide stars or tip-tilt Holography with VISIR and HAWK-I such stars is relatively high over the entire reference stars for (LGS) AO. sky this means that it is a realistic hope The primary aim of our experiment with to be able to correct HAWK-I’s large FoV Anisoplanatic effects are among the the VLT’s wide-field NIR imager HAWK-I with the holography technique. most adverse problems encountered in was to test whether holography can also AO imaging. In holography, we can deal serve to improve the image quality of On account of the necessarily short with these effects if the density of refer- ­cameras that undersample the diffraction exposure times, the mid-infrared (MIR) is ence stars is sufficiently high. The latter limit, but significantly oversample atmos- a natural regime for speckle techniques. constraint is probably fulfilled for most pheric seeing. A very brief series of 128 This was recognised at ESO many years fields in the Galactic Plane, taking into frames was taken in Ks−band during twi- ago with the implementation of VISIR’s account that stars of K = 12–13 mag can light on the core of the globular cluster burst mode. This allows VISIR observers serve as a reference. The image can M30 (in Ks-band, DIMM seeing ~ 0.9 arc- to significantly improve the image quality then be sliced into overlapping subfields seconds). Figure 4 compares a standard compared to a standard long exposure that are corrected separately and sub­ long exposure (simple average of all (Doucet et al., 2006). We tested holog­ sequently stitched together again. Thus, frames) with a holographically recon- raphy with VISIR on data obtained in May holography can work like an efficient structed image. As can be easily appreci- 2007 when the seeing was as bad as “poor man’s MCAO”. ated, the holographic image is of superb 2–3 arcseconds. A fully diffraction-­limited, quality (a Gaussian of 0.27 arcseconds full high Strehl image could be reconstructed. For different wavelength regimes, we width at half maximum [FWHM] was used A comparison between a tip-tilt corrected tested the performance of holography as TTF). Although the total integration time long exposure and the holography image successfully in the J-band (with NACO on was only 28 seconds, stars as faint as is shown in Figure 5. the core of NGC 3603, see Figure 3) and Ks ~ 20 are detected at 5σ. The high sen- I-band (FastCam at the Nordic Optical Tel- sitivity is due to the fact that more photons This experiment demonstrates that escope on the core of the globular cluster are collected­ in each pixel than when the holography can enable astronomers to M15), achieving Strehl ratios of ~ 40% and diffraction limit is sampled. This means obtain MIR images of the highest quality ~ 18%, respectively. We have also suc- that in one hour of integration time, stars even under the most adverse seeing cessfully tested holography with NACO in of Ks ~ 22 should become accessible to ­conditions. Additionally, it shows that the L(-band, with excellent results. the holography technique with HAWK-I. extended sources can be used as a PSF reference as long as they contain a point- Figure 3. Holographic image of the like object. The bright star IRS 3, which  core of NGC 3603 with NACO in sits atop extended, diffuse emission, the J-band (about 5000 frames, DIT = 0.11 seconds). The inset shows served as reference source (see Fig-  a zoom onto the region marked by ure 5). When extracting the PSFs from the black box: the two closely spaced the speckle frames, the diffuse emission stars have J = 12.0 and 12.6 mag was suppressed by flux thresholding. and a separation of 0.078 arcseconds.  Thus, the holography technique may be very useful for the study of objects such  ǥ  as active galactic nuclei or details of the 

#DB   interstellar medium in star-forming regions. Unfortunately, with VISIR’s current detec-   l tor the reference source (or sources)  ǥ    must be relatively bright, at least 1 Jy #DB

l l  (strongly dependent on seeing conditions), but we hope that significantly fainter point l  sources can be used with the new and l       l  l  more sensitive AQUARIUS detector cur- 1 ǥ rently being installed.     l l l 1 ǥ

28 The Messenger 150 – December 2012   (12         ǥ ǥ   ǥ  ǥ          DB DB DB DB     S# S# S# S# ERD ERD ERD ERD .E .E .E .E l l l l

l l l l l l l l     l l l     l l l     l l     l l .EERDS1 ǥ .EERDS1 ǥ .EERDS1 ǥ .EERDS1 ǥ

Figure 4. Holographic imaging of the core of the – backup when the AO fails to close the Figure 5. VISIR 8.6 μm observations of the Galactic globular cluster M30 with HAWK-I. Left: Standard loop on a target; Centre, taken in May 2007. Left: Tip-tilt corrected long exposure. Right: Holographic reconstruction. long exposure, PSF FWHM ~ 1 arcsecond. – high angular resolution imaging with an Right: Holographic reconstruction with a PSF FWHM instrument that is not equipped with AO; ~ 0.25 arcseconds. The brightest source in this – minimisation of systematic errors in pho- image, IRS 3, was used as reference source for the When to use holography tometry and astrometry of bright stars; image reconstruction. The vertical line running through IRS 3 is a detector or electronics artefact. – unstable AO correction with highly vari- Sagittarius A* is located at the origin. Requirements for the use of holography able PSF. on the instrumental side are a sufficiently fine spatial sampling of the detector plane In the latter case, holography can also a speckle camera minimises flexure, and and the capability of rapid readout and be applied to AO imaging data when the the lack of complicated optics may make data storage. On the target side, one or correction is unstable. By combining it a well-suited instrument for astrometry several reference stars bright enough to the ad­ ­­vantages of both techniques, holog- (and also polarimetry). be detected in individual frames are nec- raphy can enable fainter targets to be essary. Crowded fields are ideal. Holo- reached and considerably boost the per- Finally, we note that holography opens graphic imaging can be used with the formance of AO at short wavelengths, up the possibility for optical imaging near ESO VLT facility instruments VISIR, NACO with faint guide stars, or when conditions the diffraction limit of telescopes of 8 and HAWK-I, and with the guest instru- are ad­­verse. Note, however, that use metres and larger class, where lucky ment AstraLux Sur. of AO will freeze anisoplanatic effects into imaging is too inefficient. Sensitivity can the imaging data. be adjusted by an optimised trade-off Holography cannot replace AO. Particu- with spatial resolution, to enable the larly when the targets are faint (most Holography thus offers a broad range of technique to work with relatively faint ref- extragalactic observations) or when spe- novel observing possibilities for instru- erence stars. Holography may also be our cialised techniques like spectroscopy ments at ESO’s (and other observatories’) best chance to quickly realise sub-0.1 or coronagraphy are used, there is no telescopes. Our work shows how im­­ arcsecond resolution optical imaging with alternative to AO. Also, holography is not portant it is to implement and optimise the future European Extremely Large Tel- a good choice when the target and refer- fast readout modes on imaging instru- escope (E-ELT). ence star coincide, as in the search for ments. ESO’s next generation high angu- faint companions or discs around isolated lar resolution imager, ERIS, which has bright stars. In the latter case, extreme AO just successfully passed its Phase A References and techniques like sparse aperture study, should provide full support for fast Doucet, C. et al. 2006, in Visions for Infrared masking (Lacour et al., 2011) or apodising readout while maintaining good detector Astronomy, Instrumentation, Mesure, Métrologie, phase plates (Kenworthy et al., 2010) cosmetics. In addition, the novel “zero- ed. V. Coudé du Foresto, D. Rouan, & G. should be used. However there exist a noise” infrared and optical detectors Rousset, 25 broad range of situations in which holog- under development are very attractive for Eckart, A. & Genzel, R. 1996, Nature, 383, 415 Finger, G. et al. 2010, SPIE Conference Series, 7742 raphy can provide unique advantages speckle techniques because they will Girard, J. et al. 2010, SPIE Conference Series, 7742 over (single-conjugated) AO: boost sensitivity both for guide stars and Kenworthy, M. et al. 2010, The Messenger, 141, 2 – necessity for a homogeneous PSF and in the reconstructed image, by the order Lacour, S. et al. 2011, The Messenger, 146, 18 good PSF cosmetic quality over the FoV; of 2–3 magnitudes (Finger et al., 2010). Lenzen, R. et al. 2003, SPIE Conference Series, 4841, ed. M. Iye & A. F. M. Moorwood, 944 – demand for a large FoV; Primot, J. et al. 1990, Journal of the Optical Society – need for high dynamic range in a field A dedicated speckle camera can be very of America A, 7, 1598 that contains bright stars that would low cost, weight, and complexity, while Rousset, G. et al. 2003, SPIE Conference Series, saturate with AO; providing a large field of view. Holography 4839, ed. P. L. Wizinowich & D. Bonaccini, 140 Schödel, R. et al. 2012, MNRAS, in press – observations of fields devoid of AO is thus an attractive possibility to equip (arXiv1110.2261) guide stars and of suitable tip-tilt refer- any telescope with MCAO-like capabili- Sivaramakrishnan, A. et al. 2003, SPIE Conference ence stars for LGS AO; ties within a short time. The low weight of Series, 4860, ed. A. B. Schultz, 161

The Messenger 150 – December 2012 29 Telescopes and Instrumentation

The ESO 3D Visualisation Tool

Harald Kuntschner1 Given the limited manpower and time- in separate extensions of the same FITS Martin Kümmel1 frame available to the project, it was file, and how the relationship between Mark Westmoquette1 decided that extending the capabilities them is handled via FITS header key- Pascal Ballester1 of one of the already existing visualisation words. The ESO 3D visualisation tool not Luca Pasquini1 software platforms was the most practi- only has the capability of displaying the cal solution. Several possibilities were errors, but also the facilities to use them in explored and the viewer of the ALMA internal calculations or analysis proce- 1 ESO CASA software package was selected. dures. This functionality sets the tool apart The major motivations for this choice from similar software available elsewhere. were the potential for developing syner- The existence of error and quality informa- The ESO 3D visualisation tool provides gies between ALMA and VLT and the tion is desirable but not mandatory; the the capability for visualisation and basic long-term maintenance aspects. viewer can therefore also be used with 3D scientific exploitation of 3D spectro­ data without error information. scopic datasets obtained with VLT inte­ The resulting ESO 3D visualisation tool gral field unit instrumentation, includ- aims at providing the typical astronomer As part of the ESO 3D visualisation tool ing MUSE. The tool was implemented in the ESO community and also ESO project, all ESO data reduction pipelines as part of the ALMA CASA software operations staff with the means for visu- for instruments with 3D capabilities were viewer and as such provides the oppor­ alising and performing basic scientific upgraded to produce output files compli- tunity to view ALMA data as well as VLT analysis of fully calibrated and reduced ant with this new format. 3D data within the same tool. Recently, VLT datacubes of single fields. The tool the first version of the visualisation tool, allows the novice IFU user to obtain a first featuring optical and near-infrared evaluation of his/her data, as well as The viewer display panel spectroscopic capabilities, has been the more experienced IFU user to assess completed and we describe the re­ data quality in more detail. The prime purpose of any 3D viewer is leased software which is available for to visualise a datacube in a convenient Mac OS X and Linux systems. and user controlled, interactive manner. Input data The CASA viewer application consists of a number of graphical user interface Introduction With the exception of the second genera- (GUI) windows that respond to mouse tion VLT instrument SPHERE (Beuzit et and ­keyboard input. In the standard con- The majority of present and future ESO al., 2006; Kasper et al., 2012), all currently figuration, the viewer display panel (see facilities — the Very Large Telescope operational and almost completed VLT Figure 1) shows one slice (or channel) of a (VLT), the Atacama Large Millimeter/sub- 3D instruments record spatial and wave- given datacube in the main image viewer millimeter Array (ALMA), and of course length information in a way that can be (Figure 1, (a)) and allows the user to move the European Extremely Large Telescope conveniently re-sampled into a linear 3D through the slices with the animator panel (E-ELT) — feature (presently or in their grid (i.e., a datacube with uniform dx, dy (Figure 1, (b)). Crucial information on the plans) instruments which produce data- and dz). As such, the viewer requires mouse position in world coordinates as cubes (i.e., data with two spatial axes cubes to be linearly sampled in all three well as pixel-based systems is provided in plus one wavelength/frequency axis). In axes and the data to be properly de­­ the position tracker panel (Figure 1, (c)). this context, the need for an ESO-based scribed according to the FITS standard visualisation tool capable of handling (Calabretta & Greisen, 2002; Greisen In the main image viewer one can define datacubes was raised and discussed. A et al., 2006). The main difference with regions (point, rectangle, ellipse or project was set up to deliver a 3D visuali- SPHERE is that it records spatial informa- ­polygon) from which the mean, median sation tool to be used by the ESO com- tion via hexagonal lenslets projected onto or summed spectrum is displayed in the munity for the visualisation and basic sci- the sky and maintains the wavelength spectral profiler window (see Figure 2). entific exploitation of (large) 3D datasets. as recorded on the detector (to avoid re- Information on the selected region is given sampling). The SPHERE data reduction in the regions panel (Figure 1, (d)). The The development of the tool was focused pipeline, however, will also produce a lin- viewer display panel is highly configurable, on the requirements for the Multi Unit early re-sampled cube for visualisation. giving access to all important display Spectroscopic Explorer (MUSE), a VLT options such as colour tables, data dis- second generation instrument (see Bacon Starting with the second generation VLT play ranges and scalings, and the axis et al., 2006, 2012), but it includes the instruments, error arrays are commonly labels. It also allows the user to select capability of visualising data from other, provided by the data reduction pipelines. any two of the three axes of the datacube single-field integral field units (IFUs) oper- Owing to the lack of a pre-existing FITS to be displayed (e.g., right ascension ated at the VLT. In many respects, MUSE standard describing the format of error ­versus wavelength). Visualisation of non- datacubes provide a challenge to the extensions, ESO has defined a new, inter- orthogonal projections is not incorporated, viewer, not least because of their sheer nal FITS format (ESO, 2012). This format but more specialised tools are available size (2.9 Gigabytes ~ 300 × 300 × 3600 describes how science data, errors and in the public domain (e.g., Campbell, Kjær pixels) both for science and error data. data quality information should be stored & Amico, 2012). High quality images of

30 The Messenger 150 – December 2012 Figure 1. Screenshot of the main viewer panel showing one channel or slice (#284) of a (a) (b) simulated test datacube at 465.589 nm. The locations of the main image viewer (a), the animator panel (b) and the posi- tion tracker panel (c) are indi- cated on the screenshot. The (c) spectrum within the green rec- tangular region marked in the image viewer panel (a) is dis- played in the spectral profiler (see Figure 2). The position tracker panel provides crucial information on the current cur- (d) sor position such as data value, coordinates in pixels and world coordinate system (WCS) for- mat. In this example, a two- dimensional Gaussian fit to the highlighted emission region has been made. The centre and position angle is given by the magenta line and cross, respec- tively, and the numeric fit values are shown in the regions sub- panel (d).

Figure 2. Screenshot of the spectral region showing a distinct emission fea- profiler showing the mean spectrum ture was chosen. After image recon­ of the rectangular region (green) marked in Figure 1. A blue line indi- struction (a choice between mean, cates the wavelength of the slice median and sum algorithms is available) shown in the main viewer panel. In the image is displayed in the image this example a spectral range (grey viewer (not shown in Figure 1) and can shaded area) is marked by cursor interaction, which can then be used be, e.g., “blinked” with other slices of the to collapse the cube and reconstruct cube. Error estimates, derived from the an image over this wavelength range data themselves, can be optionally calcu- (in this case 552.574–570.827 nm). lated and stored together with the recon- structed image.

An often-requested application for imag- ing data is the ability to fit a simple 2D Gaussian to an object in the field of view in order to obtain estimates on the object position, extent and orientation. The viewer provides this capability as part of the regions functionality. In Figure 1 we show an example: a rectangular region around a bright emission knot is marked what is displayed in the main viewer can Analysis tool examples and a 2D Gaussian fit made. The peak is be saved in all commonly used formats automatically found, and the fit results are such as FITS, pdf, jpg or png. The spec- It is often convenient to collapse a shown graphically (magenta line and tral unit used for the display can also be ­number of datacube slices along the cross) and numerically (in the regions interactively chosen (e.g., nm, Ångström, wavelength direction to, e.g., increase panel in both pixel and world coordinate GHz), and, provided a rest frequency or the signal-to-noise level in the resulting systems; see Figure 1). wavelength is specified, can be con- “reconstructed image” or sum over an verted into units of velocity (e.g., km/s). emission line. This action is initiated from 1D Gaussian fits can also be performed the viewer display panel, opening the on the spectrum in order to determine, Beyond the basic visualisation capabili- spectral profiler where a region can be for example, the central wavelength for ties of the viewer a number of analysis interactively marked with the cursor or an emission/absorption line. We show an tools are offered. Examples are provided provided by numeric values (see Fig- example of this application in Figure 3. in the following. ure 2). In the example shown, a selected For the fit, a wavelength region is selected

The Messenger 150 – December 2012 31 Telescopes and Instrumentation Kuntschner H. et al., The ESO 3D Visualisation Tool

Figure 4. Example of spectrum visualisation with errors. A Gaussian fit (blue line) is applied to an absorption line in the grey-shaded region, including error estimates for each data point; numerical results of the fit are given at the ­bottom of the window.

Figure 3. Example of Gaussian emission line fit plus rated into the standard ALMA CASA viewer are provided by ESO via the user continuum (“poly1”) which is applied over the region ­software viewer. From CASA version 4.0 portal or by email4. General support for marked by the grey shaded area. The fit is shown in 5 blue, and the results are shown in the status bar at onwards, the features described in this the CASA software is also available . the bottom of the window. article will be available as part of the Users who make use of this tool for anal- CASA viewer. The CASA software is freely ysis of their optical/near-infrared 3D available1 and full installation is required to data are kindly requested to refer to this either by cursor interaction or numerical make use of the viewer. CASA is also part article in any publications. input. A range of fitting options, such of the ESO Scisoft software collection2. as the inclusion of a first order continuum is available. Then with a click of a button, A user manual for the viewer, particularly Acknowledgements a fit is carried out in the specified region targeted at users with optical/near-­infrared We are grateful to Dirk Petry for many fruitful discus- and the result shown graphically (blue data, has been produced as part of the sions and generous support throughout the project. solid line in Figure 3) and numerically — project. Additionally, for the somewhat the fit results with estimated errors are less patient users, we provide a “cook- provided at the bottom of the spectral book” with five simple step-by-step exam- References profiler window and on the command line. ples on how to use the relevant functional- Bacon, R. 2006, The Messenger, 124, 5 ity of the viewer. This includes examples Bacon, R. et al. 2012, The Messenger, 147, 4 The visualisation of data errors, where ranging from basic tasks such as loading Beuzit, J.-L. et al. 2006, The Messenger, 125, 29 available, was a requirement for the a cube and displaying a spectrum, to Campbell, R., Kjær, K. & Amico, P. 2012, The Messenger, 148, 28 development of the viewer. In Figure 4 obtaining a 2D fit in the image plane. The Calabretta, M. R. & Greisen, E. W. 2002, A&A, we show an example of a spectrum where manual and cookbook are available3. 395, 1077 the error estimates given in the dataset ESO, 2012. FITS format description for pipeline are displayed for each data point. Not products with data, error and data quality infor­ mation, VLT-SPE-ESO-19500-5667 only can one use the errors for visualisa- Use of the 3D visualisation tool Greisen, E. W. et al. 2006, A&A, 446, 747 tion, but they are also used, for example, Kasper, M. et al. 2012, The Messenger, 149, 17 in Gaussian line fitting, if they are dis- The ESO 3D viewer provides a way of played (see Figure 4). When no external ­visualising VLT integral field unit data Links error estimates are provided or an inde- products conveniently. An effort has been pendent estimate is desired, the tool will made to harmonise the output of the 1 CASA software available: http://casa.nrao.edu/ optionally provide error estimates derived VLT data reduction pipelines and the 2 ESO Scisoft collection: http://ww.eso.org/sci/­ from internal data statistics, e.g., for spec- interface to the viewer. If error estimates software/scisoft/ 3 ESO 3D viewer manual and cookbook available tra averaged over a user-defined region. are available in the data products — par- from: http://www.eso.org/pipelines/ ticularly relevant for second generation 4 Email for help on 3D viewer: [email protected] VLT in­­strumentation — the viewer can 5 Help on CASA software available from: Software download and documentation display the extra information and make http://almascience.eso.org/ use of errors in the internal calculations. The ESO 3D viewer for optical/near-­ infrared data originating from the VLT is Feedback and problem reports concern- not distributed separately but incorpo- ing optical/near-infrared data for the

32 The Messenger 150 – December 2012 Release eso1211. in found be can details more and combined were in images OmegaCAM 160 Mpc. about is cluster the to distance the arcminutes; 29 by 20 only is image the but 1.7 0.8 degrees, by ­ ­Hercules The image. colour (VST) Telescope Survey VLT this in 2251) shown is (Abell cluster galaxy Hercules nearby the of core central The ESO/INAF–VST/OmegaCAM. Acknowledgement: OmegaCen/Astro-WISE/Kapteyn Institute cluster has a projected size of about about of size aprojected has cluster g , -, r and - and

i - bands

Astronomical Science Astronomical Science

The La Silla–QUEST Southern Hemisphere Variability Survey

Charles Baltay1 ­variability survey that repeatedly covers 1999). Future observations of Type i a David Rabinowitz1 large areas of sky at cadences ranging supernovae are capable of probing the Ellie Hadjiyska1 from hours to days to years serves these historical expansion rate of the Universe Megan Schwamb1 goals in several ways. On hourly time- and thereby constraining the nature of Nancy Ellman1 scales, the survey exposes the motion this mysterious force. Robert Zinn2 of objects in the distant Solar System Suzanne Tourtellotte2 (­Kuiper Belt Objects or KBOs), which are The QUEST camera was installed on the Ryan McKinnon1 remnant bodies from the time of planet ESO Schmidt telescope in 2009 after pre- Benjamin Horowitz1 formation. Physical observations of these viously completing a five-year, northern Aaron Effron1 primitive objects reveal the composition hemisphere variability survey in 2008 Peter Nugent3 of the early Solar System (Barucci et al., using the 1.2-metre Oschin Schmidt tele- 2008). Also imprinted in the orbital distri- scope at Palomar. At Palomar, this cam- bution of the KBOs is a record of the era was the discovery engine for the 1 Physics Department, Yale University, early gravitational interactions that scat- Supernova Factory, leading to the meas- USA tered planetesimals outward from the urement of more than 200 spectrophoto- 2 Astronomy Department, Yale University, inner Solar System (Morbidelli, Levison & metric light curves of Type i a supernovae USA Gomes, 2008). (Kerschhaggl et al., 2011). It was also 3 Lawrence Berkeley National Laboratory, used to discover the new dwarf planets in USA On daily timescales, a variability survey the Kuiper Belt (Brown, 2008; Rabinowitz exposes the distinctive brightness oscilla- et al., 2012), to characterise the variability tions of RR Lyrae stars. These remark­ of quasars and to measure the effect of In 2009, the ESO 1.0-metre Schmidt able stars serve as precise distance mark- gravitational lensing on quasar variability ­telescope at La Silla was awakened ers, capable of revealing tidal streams (Bauer et al., 2012). This article describes from an 11-year slumber. The telescope and other large-scale structures in the the installation of the QUEST camera had been decommissioned in 1998 halo of the Milky Way resulting from past on the ESO Schmidt and the new surveys after completing a photographic survey collisions with other galaxies (Vivas et being conducted with the instrument. of the southern hemisphere. It has al., 2008). Daily observations also reveal now been given a new life with the instal­ the spectacular outbursts of supernovae lation of Yale University’s 160-mega­ in nearby galaxies and other high-lumi- The telescope upgrade pixel QUEST camera consisting of a nosity transients (Hadjiyska et al., 2012). 112-CCD mosaic covering 10 square These are interesting not only for the With the termination of the Palomar KBO degrees. The control system for the extraordinary high-energy phenomena and transient surveys in 2008, it was tele­scope was also upgraded to allow they exhibit, but also because the Type i a ­natural to look for an appropriate tele- fully autonomous observing. With the supernovae serve as cosmological dis- scope in the south to complete an all-sky new system, Yale is conducting the tance standards. Measurements of their survey for the largest KBOs and to con- La Silla­–QUEST (LSQ) Variability Survey luminosity versus redshift provided the tinue the search for supernovae, variable in the Southern Hemisphere to detect first evidence of a mysterious dark energy stars and other transients. The ideal tele- low-redshift supernovae, RR Lyrae accelerating the expansion of the Uni- scope would have a Schmidt design, like ­variable stars, Kuiper Belt Objects verse (Riess et al., 1998; Perlmutter et al., the Oschin telescope, since the QUEST (KBOs), and other unusual transients. The LSQ variability survey has already covered most of the southern hemi­ Figure 1. The 1.0-metre sphere multiple times at cadences rang­ ESO Schmidt telescope inside the dome. The ing from hours to years and to a depth QUEST camera is inside ranging from R magnitudes 20.5 to 21.5. the telescope mounted To date the survey has detected more at the prime focus. The than 65 new KBOs and thousands of camera electronics are visible on the underside new RR Lyrae stars. The detection of of the telescope tube hundreds of super­novae will lead to an with cabling running up improved measurement of the acceler­ the yoke and around the ated expansion rate of the Universe. declination axis.

The motivation for undertaking the new Schmidt surveys stems from the Yale University’s broad interests in under- standing Solar System evolution, the structure of the Milky Way and the accel- erated expansion of the Universe. A

34 The Messenger 150 – December 2012 camera was specifically designed for this Figure 2. Installation of a configuration. Fortunately, the ESO 1.0- 2-metre-diameter radio antenna on the La Silla metre Schmidt was available (Figure 1). weather tower. A match- The telescope is one of the largest ing antenna at Cerro Schmidt configurations in the southern Tololo receives the LSQ hemisphere, situated at an ideal site, image data and trans- mits them to Yale over a and has the same optical configuration high-speed internet link as the Palomar Schmidt (but smaller with the USA. entrance aperture). The QUEST camera could be installed without any changes to its front-end optics. ESO provided Yale with the opportunity to use this telescope with the expectation that Yale would update the control system for automated operation, replace the plate holder at the prime focus with the 160-megapixel QUEST camera, and establish an inde- pendent internet connection for transfer of the image data to Yale. Yale began to implement these changes in early 2009, and was ready for remote and automated operation of the ESO Schmidt by August 2009.

Since the original control system for the ESO Schmidt was over 30 years old and no longer usable, the entire system had to be upgraded. This required a complete replacement of the control electronics and Cerro Tololo, where there is direct grees, with an active area of 9.6 degrees2 for both telescope axes and the focus 100-kilometre line of sight (Figure 2). and a pixel scale of 0.87 arcseconds. mechanism, including servo amplifiers, ­Programmable radios connected to encoders, the controlling computer and 2-metre-diameter antennas were in­­stalled The focal plane is cooled with a pair of control software. With the new system with experimental software developed 60 Watt cryo-refrigerators. Each unit it is possible to run the telescope in a fully for long-distance links in developing transfers heat using a Gifford–McMahon robotic mode with no one at the tele- countries. The radio link achieves a bit cycle, where compressed helium at room scope. In typical operation, observing rate of ~ 20 Mbits/sec, sufficient to trans- temperature drives the motion of a pis- scripts are prepared at Yale during the mit the survey data to Yale as fast as they ton, thereby drawing thermal energy from day and transmitted to a computer at the are acquired. The receiving antenna at the cold head at the end of the piston telescope. At night a master scheduling Cerro Tololo connects to a high-speed program automatically sequences tele- internet backbone that is linked to the US scope pointing, dome rotation, focus mainland. sequences and camera exposures. This automation is essential for running the survey every clear night of the year. The The QUEST camera operator of the ESO 3.6-metre telescope, sitting in the main control room at La The 160-megapixel QUEST camera Silla, can monitor and control the opening ­(Figure 3) was designed and fabricated and closing of the Schmidt dome via a at Yale University in collaboration with web interface to ensure that it is closed in a group from Indiana University for initial case of inclement weather. operation at the Oschin Schmidt tele- scope at Palomar (Baltay et al., 2007). It Because LSQ must process each night was installed on the ESO Schmidt with- of survey data at Yale the day after ac­­­ out any changes to the CCD array or quisition, they require a communication the camera dewar. The focal plane con- link to La Silla that can handle ~ 50 Gbytes sists of 112 CCDs fabricated by Sarnoff per night (after compression). Unfortu- Labs. Each is a thinned, back-illuminated Figure 3. The 10-square-degree QUEST camera. nately, no such link was available at device with 600 × 2400 13 μm pixels The focal plane of the 161-megapixel camera con- sists of 112 CCD devices arranged in four rows with La Silla. Yale therefore installed a ­private, with a peak quantum efficiency of 95% 28 CCDs each. The array spans 3.6 × 4.6 degrees high-speed radio link between La Silla at 600 nm. The array covers 3.6 × 4.6 de­­ with an active area of 9.6 square degrees.

The Messenger 150 – December 2012 35 Astronomical Science Baltay C. et al., The La Silla–QUEST Southern Hemisphere Variability Survey

cylinder. Two large helium compressors sit on the dome floor beneath the tele- scope, connected by long, flexible high-    pressure lines to the piston heads. Re- circulated water cools each compressor, with the heat dissipated outside the dome by air/water heat exchangers. To minimise vibration of the focal plane induced by the piston cycling, the two cryo-refrigerators are firmly bolted to the stiff spider vanes supporting the focus hub of the telescope. Because the units mechanically connect to the camera head only by flexible copper straps and flexible vacuum housings, their vibrational energy is almost completely absorbed by the large mass of the telescope. There is no de­­tectable influence from the vibration on image quality.    

For all current surveys LSQ uses a single Figure 4. Survey areas covered to date by La Silla– survey; red areas have been covered extensively for wideband filter covering the 400 to QUEST survey are shown. The colour codes the the supernova and RR Lyrae surveys in addition to number of visits per field. Blue areas have been cov- the KBO survey. 700 nm range. The red cutoff eliminates ered at least three times per night for the KBO fringing in the images due to strong atmospheric emission lines at red wave- lengths. The blue cutoff reduces the Figure 5. The discovery images of background from moonlight. Other filter the distant KBO 2010 WG9 with mag- nitude R ~ 20.5. In each square panel sets are available, including a single plate north is up, east to the left, the image of Schott glass RG610, and sets that size is 88 by 88 arcseconds and the combine four different filters (Johnson position of the source is indicated by U,B,R,I or Gunn g,r,i,z), each covering a a white line. The time interval is ~ 2 hours between exposures. different row of CCDs in the array.

ets with sizes close to that of Pluto, ulti- cover the entire sky south of the ecliptic System performance mately leading to the new definition of a to magnitude limit R ~ 21.5, including planet that excluded Pluto from the list areas not accessible to, or not completely In the first three years of operation the of major planets. Earlier surveys covering searched by, previous northern hemi- telescope and camera have performed much smaller areas to fainter limits had sphere searches. To date, no other KBO well given that all exposures are unguided already detected hundreds of fainter surveys of comparable scale and sensi- and unmonitored during the night. Typi- KBOs and established that Pluto follows tivity have been conducted in the south. cal seeing is 1.6 arcseconds for 60 s a typical Kuiper Belt orbit. But the much Based on the discovery rate of large exposures and 2.0 arcseconds for 180 s larger size and brightness of Pluto relative KBOs at Palomar and their wide-ranging exposures. Pointing repeat­ability is to its dynamical cousins had preserved latitudes, at least a few similar-sized ~ 10 arcseconds night-to-night. Photo- its place among the planetary pantheon. KBOs likely remain undiscovered in the metric precision is ~ 1.5% for field stars Only with the discovery at Palomar of south. observed repeatedly over many nights. other bodies like Pluto, massive enough The only serious instrumental problem to gravitationally retain a surface rich in The sky coverage of the KBO survey is was a failure of the support wheels for the ­volatile ices, did it become clear that Pluto shown in Figure 4. Each survey area has dome owing to the aging of rubber com- was not unique. But of more importance been covered at least three times per ponents. This has now been fixed by a to our understanding of the origin and night for the KBO search. More than 65 complete replacement of the old wheels evolution of the Solar System, the discov- new KBOs have been detected, including with new bogies designed by G. Ihle. ery of the dwarf planets has led to a redetections of the dwarf planets Eris new understanding of KBO composition and Sedna. However, no new objects and structure, volatile retention, collisional larger than ~ 500 kilometres have yet The search for KBOs dynamics, surface weathering and dy­­ been discovered. One of the most inter- namical evolution. esting new objects is 2010 WG9, a dis- In recent years, surveys for KBOs con- tant body with an inclination exceeding ducted with the QUEST camera have The LSQ survey further explores the pop- 70 degrees and a perihelion near the exposed a new population of dwarf plan- ulation of large KBOs. It is intended to orbit of Uranus. The discovery images are

36 The Messenger 150 – December 2012 shown in Figure 5. Only two other bodies Figure 6. Discovery subimages for are known with similarly high inclinations the Type i a supernova LSQ11ot, red- shift 0.026, showing the reference, and distant perihelia. As with long-period new and subtracted images (left to comets, commonly observed when they right, upper panel). The subimages are pass into the inner Solar System, 2010 each 0.94 by 0.94 arcminutes. The WG9 is likely a returning member of the host-subtracted light curve for the Type i a supernova LSQ11bk, redshift Oort Cloud. However, it has somehow 0.03, is shown (lower panel). managed to follow an unusual path allow-  ing Uranus or Neptune to capture the orbit and prevent a closer passage. As such, it may be one of the few observed bodies from the Oort Cloud unaltered by a close passage to the Sun. Observa- tions to determine its physical properties 

are in progress. @F L 1 l The Supernova Survey 42-.  Type i a supernovae have recently re­­ ceived much attention as calibratable standard candles in cosmological stud- ies, particularly for the role they play in the discovery of the acceleration of the expansion of our Universe. In order to  carry these studies to an increased level     of precision, a number of surveys have )#l gathered samples of relatively high red- shift supernovae. Additional high redshift field can be made. Subsequent observa- by collaborators, including the Public surveys are being planned, including the tions of the field can then be sent through ESO Spectroscopic Survey of Transient Large Synoptic Survey Telescope (LSST) the LSQ subtraction pipeline, which sub- Objects (PESSTO) which uses the EFOSC and the space mission WFIRST. As the tracts the reference image from each new spectrometer on the ESO New Technol- detections at high redshift become image and detects transients by identify- ogy Telescope (NTT), located just a few numerous, there is new scientific motiva- ing the residual sources in the subtracted hundred metres from the ESO Schmidt. tion to carry out a large-scale survey images. for low-redshift supernovae. In particular, the low-redshift sample anchors the On a given night, typically ~ 1000 poten- The study of RR Lyrae variables ­Hubble Diagram at the most recent epoch tial transients are detected and must be of expansion. Measurements of the visually scanned to remove noise arte- The properties of the halo of our galaxy nearby supernovae are necessary to facts. Of the remaining candidates, those and how they may be explained in the reduce the error obtained on the resulting that appear near or on top of galaxies broader context of galaxy evolution has cosmological parameters. Also, detailed and have historical variability inconsistent been an active area of research for many physical studies of the low-redshift with variable stars are scheduled for years. Early models assumed a smooth supernovae improve our understanding spectroscopic follow-up. Figure 6 shows uniform distribution of stars in a halo of their ensemble properties and their use LSQ discovery images for one Type i a formed during the early stage of collapse as distance indicators. supernova and a light curve of a second of our galaxy. Recent studies however one, both discovered at low redshift. suggest that accretion of satellite galax- In order to detect supernova, the LSQ ies has played a major role in the for­ survey covers a given set of fields repeat- The area covered to date by the super- mation of the Halo, leaving significant edly, usually with a two-day cadence nova survey is shown in Figure 4 (red structure inside the Halo. RR Lyrae are (set A is covered on the first night, set B areas). The search has been concen- periodic variable stars with uniform intrin- on the second, repeat set A on the third, trated between –25 and +25 degrees sic luminosities, hence they make excel- repeat set B on the fourth, and so on). declination to allow follow-up by both lent standard candles for probing the Similar to other surveys, LSQ uses a roll- northern and southern observers. Most structure of the Galactic Halo. LSQ has ing search, repeating observations of of this area has been covered in excess been used to gather a large sample of RR most of the fields in these two sets for of 40 times in the last three years. Several Lyrae stars, providing sensitivity to rem- several months. Once a particular field hundred supernovae have been discov- nants of galaxy mergers in the Halo. In a has been observed multiple times in ered. More than 100 have been followed search of 1300 square degrees, a total good conditions, a reference image of the up and confirmed spectroscopically of about 2000 RR Lyrae variables were

The Messenger 150 – December 2012 37 Astronomical Science Baltay C. et al., The La Silla–QUEST Southern Hemisphere Variability Survey

found with magnitudes between 14.5 and Figure 7. LSQ light 20.5, corresponding to distances from 14.5 obj12574 < V > = 14.93 curve measurements of a few typical RR Lyrae 6 to 100 kiloparsecs. Figure 7 shows a variable stars. The few representative light curves. 15 observations are phased by the light- curve period and photo- metrically calibrated Future plans 15.5 15.5 using Sloan Digital Sky obj10770 < V > = 16.09 Survey field stars. In collaboration with other institutions in the United States and PESSTO, Yale g. 16 ma

­University plans to continue the LSQ V supernova survey for several more years. 16.5 A new survey for high-inclination KBOs is also planned, with the search area con- centrated near the ecliptic pole and 18.5 obj5381 < V > = 19.27 pushed to fainter magnitudes in order to find more unusual bodies, like 2010 WG9. 19 The cooperative working relationship 19.5 between Yale University and ESO staff at La Silla has been extremely fruitful, leading 20 to a revitalised observing programme with 00.5 11.5 the ESO Schmidt. The collaboration prom- Phase ises to yield many exciting discov­eries in the years to come, spanning the range from planetismals to exploding stars. La Silla to Cerro Tololo. Many other unnamed friends Bauer, A. et al. 2012, ApJ, 749, 56 and colleagues generously contributed their time to Brown, M. 2008, in The Solar System Beyond make LSQ possible. The work was supported by Neptune, ed. M. Barruci et al., Univ. Arizona the US Department of Energy and NASA. The Press, 335 Acknowledgements National Energy Research Scientific Computing Hadjiyska, E. et al. 2012, Proc. IAU, 285, 324 Center provided staff and computational resources. Kerschhaggl, M. et al. 2011, PrPNP, 66, 335 We thank Andreas Kaufer for his cooperation in Morbidelli, A., Levison, H. & Gomes, R. 2008, making the La Silla–QUEST project possible. We in The Solar System Beyond Neptune, ed. also thank Gerardo Ihle and the technical staff at References M. Barruci, et al., Univ. Arizona Press, 275 the La Silla Observatory for their outstanding efforts Perlmutter, S. et al. 1999, ApJ, 517, 565 both during the installation and the operation of Baltay, C. et al. 2007, PASP, 119, 1278 Rabinowitz, D. et al. 2012, AJ, 144, 140 this survey. We are also grateful to Hans-Werner Barucci, M. et al. 2008, in The Solar System Beyond Riess, A. et al. 1998, AJ, 116, 1009 Braun, Jim Hale, and Sam Leffler for their help in the Neptune, ed. M. Barruci, H. et al., Univ. Arizona Vivas, A. et al. 2008, AJ, 136, 1645 design and implementation of the radio link from Press, 275

A photograph of the 1-metre Schmidt telescope on La Silla taken in 1971 during its first test period is shown. Otto Heckmann, the first ESO Director ­General, is standing in front of the telescope.

38 The Messenger 150 – December 2012 Astronomical Science

β Pictoris, a Laboratory for Planetary Formation Studies­

Anne-Marie Lagrange1 estimated to be 200 Myr, and its distance et al., 2012), in which the parent kilo­ Gaël Chauvin1 16 pc). The dust distribution revealed a metre-sized bodies are mainly located in flat, edge-on disc, detected between 100 a narrow (10–20 au) wide ring at about and 400 astronomical units (au) from 90–100 au (planetesimal disc). Collisional 1 Institut de Planétologie et the star. The β Pic disc became a proto- cascades produce small grains detected d’astrophysique de Grenoble, France type of the debris discs that contain sub- out to several hundreds of au because stantial amounts of grains, short-lived of the radiation pressure of the star, while against destructive (collisions) or removal an additional component of hotter dust Shortly after its discovery in 1984, the (radiation pressure, Poynting–Robertson is also needed to account for the IR data. Beta Pictoris disc was recognised as drag) processes and therefore needing a possible site of past, ongoing or ­fu­­ture replenishment through collisional cascade Shortly after the discovery by dust imag- planet formation. It has since been or evaporation from large, kilometre-sized ing, circumstellar gas was detected in observed extensively, from the X-ray bodies down to micrometre-sized grains. absorption using high spectral resolution domain to centimetre wavelengths optical spectrographs and in the ultra­ by many ground- and space-based Debris discs trace the stages of planetary violet with the International Ultraviolet ­telescopes. The disc has become a system evolution where solid bodies sig- Explorer (IUE) satellite. The first optical remote laboratory to study the physical nificantly larger than primordial dust are data were obtained in late 1984 with the and chemical characteristics of debris present (see Lagrange et al. [2000] for an high resolution Coudé Echelle Spectro- discs. Recently, we were able to detect early review). Since 1984, the β Pic disc graph (CES) at the Coudé Auxiliary Tele- a companion orbiting the star at a has been extensively observed from opti- scope (CAT) on the ESO 3.6-metre tele- ­distance comparable to that of Saturn cal to millimetre wavelengths (see Fig- scope at La Silla (Hobbs et al., 1985; in our Solar System. The β Pic system ure 1). Briefly, optical and near-IR obser- Vidal-Madjar et al., 1986, see Figure 2a). thus offers a unique opportunity to vations have provided high spatial re- Repeated observations with CES and study giant planet properties and solution, scattered light images tracing IUE revealed im­portant infalls of high planet/disc interactions. We present a small grains; thermal data provided by velocity ionised gas (a few tens to a few short — and necessarily incomplete — medium resolution images have demon- hundreds of km/s), packed in clumpy review of the main discoveries made strated the presence of hotter dust, while structures with sizes smaller than that of in this fascinating system over three (sub-)millimetre images have traced larger the star (e.g., Lagrange et al.,1988), decades of observations, a number of grains, and consequently, the parent ­attributed to evaporating comets grazing which were achieved with ESO tele­ bodies as well. Thanks to all these obser- the star. Intensive monitoring of these scopes. vations, we now have a schematic view gaseous infall events in the late eighties/ of the disc (Augereau et al., 2001; Wilner early nineties as well as detailed modelling

The debris disc, its gas and kilometre- Figure 1. Images of the sized bodies a) b) β Pic disc at various N wavelengths: a) optical One of the most challenging topics in observations with Las astronomy today is certainly to under- Campanas 2.5-metre at stand how planetary systems, with all E 890 nm obtained in their complexity (planets, comets, dust April 1984 (from Smith & Terrile, 1984); b) mid- and gas) form and evolve. Even though infrared observations at sketches of the formation of the Solar 12 μm with the ESO System have been developed and simu- 3.6-metre and TIMMI lated since the late 1960s, additional (from Lagage & Pantin, 1994); c) near-infrared examples of planetary systems were 30ǥ 1ǥ coronagraphic imaging lacking to explore their possible variety. in J-band with ESO The discovery of infrared (IR) excesses 3.6-metre and the associated with T Tauri stars and then c) d) Adonis instrument (from Mouillet et al., 1997); with main sequence stars were the first d) near-infrared Ks-band steps in the study of star and planet images with VLT and ­formation. In 1984, IRAS measured IR NACO (Lagrange et al., excesses associated with a few main 2012a). sequence stars that were attributed to cold dust, perhaps related to planet for- mation (Aumann, 1984). Shortly after, Smith & Terrile (1984) imaged the dust +8 around one such star, a young (12 –4 Myr) and close (19.3 ± 0.2 pc) A5V star β Pic 2ǥ 1ǥ (note that at that time, its age was rather

The Messenger 150 – December 2012 39 Astronomical Science Lagrange A.-M., Chauvin G., Beta Pictoris, a Lab. for Planetary Formation Studies­

a) Figure 2. a) Early Ca ii spectrum of β Pic d) (Hobbs et al., 1985): The stable gas produces a deep and narrow component at the bottom 300 Na I D NE of the rotationally broadened stellar line. 2 b) In addition to the centred stable circum­ stellar line, variable redshifted Ca ii is also observed (Vidal-Madjar et al., 1986); from CES data. c) Simulations of the redshifted 200 absorption produced by an evaporating comet grazing the star as illustrated on the

Relative intensity 2Å β Pic small upper panel (from Beust et al., 1990). d) Resolved Na i emission observed in the β 100

Pic disc with VLT UVES; the gas is shown u)

to be on a Keplerian orbit (Brandeker et al., (a 2004). 0 b) c) distance 3 d

Stellar distance (au) te

0 0.05 0.1 0.15 0.2 ec 4 2 Proj –100 0.02

2 0 0 –2 0.02 –4 – –200 0 10 20 30 Stellar distance (R) Relative intensity 1 Q = 5.98 × 106 kg/s Ion: Ca II z at 1 au = 6 × 1032 s–1 5 –300 SW K line 4 FWHM = 9.3 km/s –30–20 –10 0 10 20 30 0 v = 42.6 km/s –5050 0 100150 3 log(N) = 11.7 Radial velocity (km/s) Heliocentric velocity (km/s) 2

Relative intensity 1

0 –5050 0 100 150 Heliocentric velocity (km/s)

(e.g., Beust et al, 1990, see Figure 2c) Early indications of planets in the β Pic has been done to our knowledge for strengthened the “falling evaporating system the β Pic disc. bodies” (FEB) scenario which still holds − Photometric data recorded at the Swiss after more than 20 years of observations. The presence of planets in the β Pic disc telescope in the early eighties on β Pic On the contrary, there is still no consen- had been suspected since the 1990s (which used to be regarded as a photo- sus concerning the explanation for the from several independent considerations: metric standard) were re-analysed in stable gas around the star, seen either in − The mere presence of short-lived dust, the nineties and revealed that intriguing absorption or in emission, in particular produced by destruction (collision, variations had occurred on 10 Novem- species that are expected to be very evaporation) of kilometre-sized bodies ber 1981. Explanations involving either short-lived because of photodissociation, indicated that at least the building a multiple giant cometary tail or a trans- photoionisation or radiation pressure, blocks of planets were already present iting planet were proposed to account such as CO, CI, etc (Lagrange et al., in the system. The gravitational pertur- for the observed variations (Lecavelier 1998; Roberge et al., 2000; Brandeker et bation of a giant planet on cometary- et al. [1997] and references therein); al., 2004; Nilsson­ et al., 2012; see Fig- like bodies was found to be the best − Thermal infrared data show inhomoge- ure 2d). In any case, the total amount of explanation for the observed rate of neities in the disc: belt-like structures gas in the β Pic system is significantly comet infall. Dedicated simulations or clumps that could be due to sculpt- smaller than that around younger (a few concluded that such a planet (a giant ing by planets located in the gaps (see Myr) systems such as Herbig stars or T planet) should be located within 10 au ­Freistetter [2007] for more detail). In Tauri stars, in agreement with the estima- of the star (Beust & Morbidelli, 2000). particular, the latter, a 2–5 Jupiter mass tions of primordial disc dissipation time- − The presence of a relative void of mate- planet at about 10 au, was proposed scales of about 3–6 Myr. rial in the inner parts of the disc was by Freistetter (2007); also attributed to the sweeping up of − In the late 1990s the Hubble Space material by planets. This generic mech- ­Telescope (HST) and ESO 3.6-metre anism has also been invoked in other Adonis adaptive optics high spatial res- instances, but no dedicated modelling olution data at optical/near-IR wave-

40 The Messenger 150 – December 2012 Figure 3. NACO L´ -band 2003 (Lagrange et al., 2009, see Fig- images of β Pic b are ure 3). Its apparent magnitude of L´ ≈ 11.2 shown: in 2003 (left) with star-planet separa- indicated that, if bound to the star, it had tion ~ 400 milliarcsec- a tem­perature of ~ 1500 K and a mass onds; in 2009 (right) with of about 8 MJupiter according to the hot- separation ~ 300 milli- start planet models from the Lyon group arcseconds. From Lagrange et al. (2009; (Baraffe, 2003). We had to wait until 2010). autumn 2009 to see this object again, this time 0.3 arcseconds southwest from the star and to confirm that it was indeed 0.5ǥ bound to the star (Lagrange et al., 2010). In the meantime, the companion had travelled about half an orbit behind the lengths revealed the presence of an None of these considerations proved that star. Subsequent NACO monitoring inner warp in the scattered-light planets were indeed present, however allowed us to resolve the orbit of β Pic b images, extending up to a few tens of altogether they formed a very indicative (Chauvin et al., 2012) and constrain the au (Burrows et al., 1995; Mouillet et set of clues. semi-major axis of the planetary orbit al., 1997). Dynamical simulations to the range 8–12 au, most probably at allowed us to show that a massive 8–9 au, that is within the orbit of Saturn companion on a slightly in­­clined orbit A giant planet at about 9 au in the Solar System (Figure 4). β Pic b is with respect to the outer disc mid- then located in the region where, accord- plane could explain the warp, provided Using NACO on the VLT, we detected ing to current formation models, and its mass (M) and separation (a) fulfilled a faint source about 0.4 arcseconds given the star age and mass, giant plan- a constraint on M×a2 (­Mouillet et al., northeast from the star, roughly along the ets can have formed in situ by core 1997; Augereau et al., 2001). disc direction, in data taken in November accretion, like the giant planets of the

Figure 4. Ks-band Image of β Pic b in - -$ April 2010 (from Bonnefoy et al., 2011) is shown (upper left). The astrometric  $   monitoring of β Pic b relative to β Pic is reported in the lower plots. The pre-     dictions for the position of β Pic b in   case of a background source are

T     SN$@QSG reported in gray from 10 November @  2003 to 26 March 2011 (lower left). A Ⱦ ,@Q   \      %DA   zoomed view of the most recent astro-    metric observations over 2010 and   -NU      2011 is presented at lower right. At   2DO       upper right, details of the orbit of `/HBSNQHRA      OQ   l  #DB   β Pic b from Chauvin et al. (2012) for    L@R  .BS   two possible solutions of low (e = 0 in 26 -NU   green) and slightly higher eccentricity (e = 0.16 in red) are illustrated. l     WȾ@T 

  −250 25/10/09 29/12/09  −300 10/04/10 

@R 28/09/10

 (mas) Δδ 16/11/10 b L −350 17/11/10 6 01/02/11 26/03/11  −400 (%!*&  −100 −150 −200 −250 Δα (mas)

     6_L@R

The Messenger 150 – December 2012 41 Astronomical Science Lagrange A.-M., Chauvin G., Beta Pictoris, a Lab. for Planetary Formation Studies­

  Figure 5. Upper: Radial ers, whereas more mature (and colder) velocity variations of counterparts would not be so easily β Pic (from Lagrange et al., 2012a) observed detected. Whether these hot-start mod-   with ESO 3.6-metre and els could apply to planets formed by core

 HARPS are plotted accretion is obviously questionable. R together with the NACO

JL   images of β Pic b. X Centre: Slope of the A first attempt to model core accretion radial velocity induced was made by Marley et al. (2007), assum- DKNBHS

U by a planet of different l  ing significant loss of energy during the masses with a 7400-day accretion shock of the gas onto the

1@CH@K period, similar to that of β Pic b, when using planet core. This resulted in initial internal l  the available data sam- entropies much lower than assumed so pling; the horizontal lines far and, consequently cooler young giant indicate the upper level planets, much less luminous at young of the slope (3 σ) derived l  ages. However, according to this model,        from β Pic radial velocity )#l data. For each mass, all 12-Myr-old giant planets would be the various points corre- much fainter than β Pic b. Recent, more spond to different noise  — l detailed studies (Mordasini et al., 2012; realisations. Lower: Cur- rent detection limits in priv. com.) indicate that the observed the β Pic system, cou- luminosity of β Pic b could be compatible  —l pling data from different with a planet formed with small energy instruments, especially loss during this gas accretion shock.

 HARPS, VLT adaptive

@X Clearly, current evolutionary models to l optics and VLTI Pionier, C  —

R and showing the poten- predict the properties of giant planets still

JL tial role of the forth­ need some tuning; they also need calibra-  coming VLT instrument tions, i.e. measurements of planet fluxes  —l SPHERE. 2KNOD and independent (astrometric, veloci­ metric) measurements of their masses.  To possibly constrain the mass of β Pic b, we analysed high precision HARPS data collected over eight years since 2003 l —l (Figure 5, top panel) and found that the    

/K@MDSL@RR,ITO dynamical mass of β Pic b is less than 10, 12 and 15.5 MJup if orbiting at 8, 9 1000 and 10 au respectively (Lagrange et al., 2012a). These results illustrate how ­crucial the combination of radial velocity 100 data and direct imaging might be. ) p Ju

M 10 (/ Disc–planet interaction M 1 A subsequent question is whether the β Pic b planet can explain the character- istics of the disc morphology and, in 0 0.01 0.10 1.00 10.00 100.001.000.00 ­particular, its inner warp. Using the con- Semi–major axis (au) straints derived from our 2001 dynamical studies, and taking into account the Solar System, rather than by disc gravita- β Pic b, as well as those of all other im­­ updated mass and age of the system, we tional instability (the latter mechanism aged planets, relies on model-dependent found that indeed it could, provided it being rather inefficient at a few au). brightness–mass relationships. So far, orbited on a slightly inclined orbit. We the hot-start models have been used; they recorded new data in which the disc and Further imaging at Ks (Bonnefoy et al., assume that the giant planet is formed the planet could be seen simultaneously 2011; see Figure 4) and at 4.0 µm (Quanz by the collapse of a gaseous cloud and (to minimise astrometric uncertainties) et al., 2010) led to mass estimates for that the energy released from accretion is and that allowed us to conclude that the β Pic b similar to those deduced from entirely converted into heat. The young planet is not orbiting in the plane of the L´-band data, again using the hot-start planet is therefore still quite hot during its outer disc, but most probably in the models (Baraffe, 2003). It has to be first 100 Myr, and within the reach of warped part of the disc (Lagrange et al., stressed that the mass determination of detection by current/forthcoming imag- 2012b). Finally, order of scale considera-

42 The Messenger 150 – December 2012 tions show that β Pic b could also be β Pic among other debris discs References responsible for the FEBs at the origin of Augereau, J. C. et al. 2001, A&A, 370, 447 the replenishment of the disc gas phase, β Pic is, so far, the most studied example Aumann, H. H. 1984, BAAS, 16, 483 but new modelling is still needed to of the debris discs. Such discs are Baraffe, I. et al. 2003, A&A, 402, 701 ascertain this point. favourable places to search for planets, Beust, H. et al. 1990, A&A, 236, 202 especially those around young stars, Beust, H. & Morbidelli, A. 2000, Icarus, 143, 170 Bonnefoy, M. et al. 2011, A&A, 528, L15 such as β Pic, as the planets are Brandeker, A. et al. 2004, A&A, 413, 681 Future work expected to be brighter than their older Burrows, C. J., Krist, J. E. & Stapelfeldt, K. R. 1995, counterparts and, unlike younger sys- AAS, 187, 3205 An unprecedented set of data has been tems, most of the primordial material has Chauvin, G. et al. 2012, A&A, 542, 41 Freistetter, F., Krivov, A. V. & Löhne, T. 2007, A&A, gathered on the β Pic system over some been expelled, or has accreted into 466, 389 28 years and remains unique in several ­planets, and therefore does not set a limit Hobbs, L. M. et al. 1985, APJ, 298, 357 aspects. The disc provides the opportu- on planet detection. Discs with peculiar Kalas, P. et al. 2008, Science, 322, 1345 nity to study, in great detail, the physical structures such as rings with sharp Lagage, P. O. & Pantin, E. 1994, Nature, 369, 628 Lagrange-Henri, A. M., Vidal-Madjar, A. & Ferlet, R. and chemical characteristics of sites edges or asymmetries and spirals, possi- 1988, A&A, 190, 275 of ongoing, or recently completed, plane- bly shaped by planets, are thought to Lagrange, A.-M. et al. 1998, A&A, 330, 1091 tary formation. Knowledge of the system be even more interesting targets, even Lagrange, A.-M., Backman, D. & Artymowicz, P. has improved a lot, but at the same time though we know that other physical 2000, in PPiv, Univ. of Arizona Press, 639 Lagrange, A.-M. et al. 2009, A&A, 493, L21 many questions are still unanswered. effects not involving planets can also lead Lagrange, A.-M. et al. 2010, Science, 329, L57 What is the origin of the stable gas in the to the formation of such structures Lagrange, A.-M. et al. 2012a, A&A, 542, 40L system? What do the dust and gas tell (Takeuchi & Artymowicz, 2001; Lyra & Lagrange, A.-M. et al. 2012b, A&A, 542, 18 us about planet formation? In that con- Kuchner, 2012). It is remarkable however Lecavelier Des Etangs, A. et al. 1997, A&A, 328, 313 Lyra, W. & Kuchner, M. J. 2012, arXiv1204.6322L text, a very valuable piece of information that all the stars (as yet only three exam- Marley, M. S. et al. 2007, ApJ, 655, 541 is also expected from ALMA, as indicated ples are known) around which relatively Marois, C. et al. 2010, Nature, 468, 1080 by the spectacular (yet uncalibrated) test close (≤ 120 au) planets have been Mouillet, D. et al. 1997, MNRAS, 292, 896 image. How did β Pic b form? Are there imaged are surrounded by debris discs: Nelson, R. P., Lagrange, A.-M. et al. 2001, A&A, 370, 447 other planets in the system, as expected Fomalhaut (Kalas et al., 2008); HR8799 Nilsson, R. et al. A&A, 544, 134 if the observed dust rings/clumps are (Marois et al., 2010) and β Pictoris. Quanz, S. P. et al. 2010, ApJ, 722, 49 indeed due to planets? Our exploration of Thanks to instruments offering increased Roberge, A. et al. 2000, 538, 904 the planet content will significantly im­­ spatial resolution and/or sensitivities Smith, B. & Terrile, R. 1984, Science, 226, 1421 Takeuchi, T. & Artymowicz, P. 2001, ApJ, 557, 990 prove in the future thanks to forthcoming (VLT/SPHERE, the European Extremely Telesco, C. M. et al. 2005, Nature, 433, 133 VLT/SPHERE and Gemini/Gemini Planet Large Telescope and the James Webb Vidal-Madjar, A. et al. 1986, A&A, 167, 325 Imager high resolution instruments, Space Telescope), planet searches Wilner, D. J., Andrews, S. M. & Hughes, A. M. 2011, and to the combination of the results with will become possible for an increasing ApJ, 727, 42 radial velocity or astrometric data (see number of targets, allowing a wider Figure 5, bottom panel). exploration of the diversity of planetary systems and their formation processes.

Image of the Galactic H ii region Sharpless 2-292 (also known as RCW 2 and Gum 1) taken with the MPG/ESO 2.2-metre telecope and the Wide Field Imager. The main source of ionisation of the nebula is the central bright Be star HD 53367. The ionised gas is visible in Hα emission and other filters of this composite image were B, V and R. Further details can be found in Release eso1237.

The Messenger 150 – December 2012 43 ESO/VVV Consortium | Acknowledgement: Ignacio Toledo, Martin Kornmesser A logarithmic stellar density map of the central 20 by 15 degrees of the Galactic Bulge created by the VISTA variables in the Vía Láctea (VVV) public survey team. See Release eso1242. Astronomical Science

RS Puppis: A Unique Cepheid Embedded in an Interstellar Dust Cloud

Pierre Kervella1 remnant of the interstellar material from on the three-dimensional distribution of Antoine Mérand2 which the Cepheid formed. the scattering material, and the position László Szabados3 of the observer (see, e.g., Sugerman William B. Sparks4 [2003] for details). Figure 2 shows a sche- Alexandre Gallenne5 Light echoes: a stimulating geometrical matic view of the propagation of the Robert J. Havlen6 puzzle ­maximum light wavefronts emitted by RS Howard E. Bond4 Pup into space. The geometrical shape Emanuela Pompei2 Cepheids are historically the most im­­ of these wavefronts is almost a parabo- Pascal Fouqué7 portant class of variable stars, thanks to loid (rigorously, they are very elongated David Bersier8 the relation between their pulsation pe­­ ellipsoids). Their intersection with a thin Misty Cracraft4 riod and absolute luminosity; that relation light-scattering dust layer produces “light played a key role in the discovery of the rings”, such as those visible in Figure 1 expansion of the Universe. In particular, (right). For the nebula of RS Pup, the 1 LESIA, Observatoire de Paris, UPMC, long-period Cepheids are so bright that irregular distribution of the dust results in Université Paris Diderot, France they can be observed in very distant imperfectly circular rings. 2 ESO ­galaxies, and act as standard candles to 3 Konkoly Observatory, Hungary measure their distances. With its 41.4- Light echoes are particularly interest- 4 Space Telescope Science Institute, USA day pulsation period, RS Pup is one of ing as they may provide a means of 5 Universidad de Concepción, Chile the brightest known long-period Cepheids measuring the geometrical distance to 6 307 Big Horn Ridge Dr., Albuquerque, in the Galaxy. But this star also stands the central star. For a Cepheid like RS USA out as the only known example of the inti- Pup, such an independent distance 7 IRAP, Université de Toulouse, France mate association of a Cepheid with a measurement is of great interest for the 8 Astrophysics Research Institute, dust cloud (Figure 1, left). The discoverer calibration of the Period–Luminosity rela- ­Liverpool John Moores University, UK of the nebula of RS Pup, Bengt Westerlund tion. From imaging of the light echoes (Westerlund, 1961), has already remarked with the ESO Multi-Mode Instrument on that “the nebula may be large enough the New Technology Telescope (NTT/ The long-period Cepheid RS Pup illu­ to permit the detection of pos­sible varia- EMMI), Kervella et al. (2008) derived its minates its circumstellar dust cloud tions in its intensity dis­tribution due to distance based on the assumption that with a variable flux, and creates spec­ the light variations of the star”. The exist- the observed nebular features are located tacular light echoes. Through photo­ ence of this “light echo” phenomenon, close to the plane of the sky. However, metric observations of this phenome­ created by the propagation of the lumi- as argued by Bond & Sparks (2009), this non with NTT/EMMI, and polarimetric nosity variations of the star in the nebula, simplifying assumption could lead to a imaging with VLT/FORS, we have was subsequently confirmed by Havlen significant bias on the determined dis- ­de­­rived the geometric distribution of (1972). tance. To derive the distance of RS Pup the scattering dust and the total mass unambiguously using its light echoes, of the nebula. We conclude that the The geometrical configuration of the light we therefore need first to determine the dust was not created by mass loss from echo phenomenon is somewhat counter- three-dimensional geometry of the dust the Cepheid, but is most probably a intuitive, as its morphology depends both nebula.

Ma ximu Minimu m ligh t m ligh Towards the Earth 0 t Z r R

RS Pup y sk

Figure 1. Left: Three-colour BVR e th composite image of the nebula of RS e of

Pup obtained using the NTT/EMMI an Pl instrument. Upper: Ratio of two Light–scattering dust layer images obtained a few days apart, showing the light echoes (from Kervella et al., 2008). Figure 2. Geometry of the propagation of the maxi- mum and minimum light wavefronts in space, for an observer located to the left of the figure.

46 The Messenger 150 – December 2012 The first piece of information on the dust 7.5 of the degree of linear polarisation over geometry is provided by the high contrast the nebula (Figure 4, upper right). The of the light echoes in the nebula. The altitude Z of the dust layer relative to the 8.0 ­relative amplitude of the photometric vari- plane of the sky is obtained in the same ation on any part of the nebula is compa- e physical units as the projected distance rable to the variation of the central star 8.5 R. As a consequence, to obtain the alti-

itself. As shown in Figure 3, the amplitude magnitud tude in absolute linear units, we have to of the luminosity variation of RS Pup is B assume the distance of the star to be relatively large, particularly in the B-band 9.0 1.8 ± 0.1 kpc (estimated from in­­direct (there is almost a factor of five between techniques). The resulting altitude map is the minimum and maximum luminosity). 9.5 presented in Figure 4 (lower left). The fact that this high amplitude is pre- –0.2 0.0 0.20.4 0.6 0.81.0 1.2 served in the scattered light indicates that Phase The light-scattering material surrounding the dust is confined in a geometrically Figure 3. The light curve of RS Pup in the B-band RS Pup appears to be spread over an thin veil, as a thick layer would result in (data from Berdnikov et al. [2009]). irregular surface, with no well-defined the out-of-phase super­position of differ- central symmetry relative to the Cepheid. ent wavefronts, and therefore the disap- on the Very Large Telescope (VLT/FORS; The visual shape of the nebula (Figure 4, pearance of the echoes. Kervella et al., 2012). The resulting pola­ri­ upper left) appears more symmetric, metric images allowed us to derive a map due to the higher efficiency of forward To determine the spatial shape of this dust layer, we used the particular linear polarisation signature of the scattering of light by dust grains. The degree of lin- ear polarisation ρ of the scattered light is linked to the scattering angle θ, i.e., the angle between the incident and emergent directions of the photon (see Figure 2). The maximum polarisation is ~ 50% for a scattering angle of θ = 90°, i.e. for scat- tering material located in the plane of the sky, and a zero polarisation degree is obtained for forward or backward scat- tering (θ = 0 or 180°). We used the empir- ical calibration of the ρ(θ) relation ob­­ tained by Sparks et al. (2008) from the light echo of the cataclysmic variable star

V838 Mon. This relation is very close 015002000 1500 000 2500 3000 3500 00.050.1 0.15 0.20.250.3 0.35 0.40.45 to the theoretical scattering law for very small dust grains (Rayleigh scattering). From a measurement of ρ, we can there- fore retrieve the scattering angle θ.

The projected angular separation R is directly measured in the images, and by combining R and θ, we can estimate the altitude of the scattering material Z = R/tan(θ) above the plane of the sky (i.e. the imaginary plane orthogonal to the line of sight, located at the distance of RS Pup). It should be noted that backward scattering is much less efficient than for- ward scattering, and we therefore observe essentially the material located between

RS Pup and us, while the dust located 0.20.3 0.40.5 0.6 0.70.8 0.91 01020304050607080 behind RS Pup will be very much fainter. Figure 4. Upper left: FORS+EMMI combined intensity front of RS Pup, relative to the plane of the sky (in To measure θ for each point of the nebula, image of the nebula of RS Pup in the V-band (field parsec). Lower right: Density of the scattering mate- of view 4 by 4 arcminutes). Upper right: Map of the rial (in units of 1054 H atoms per square arcsecond, we took advantage of the polarimetric degree of linear polarisation measured with FORS. i.e. the equivalent number of hydrogen nucleons in imaging mode of the FORS spectrograph Lower left: Altitude of the light-scattering dust layer in the scattering material). From Kervella et al. (2012).

The Messenger 150 – December 2012 47 Astronomical Science Kervella P. et al., RS Puppis: A Unique Cepheid Embedded in an Interstellar Dust Cloud

Figure 5. Images of the nebula surrounding RS Pup in the V-band (EMMI, left), and Spitzer infrared images at 24 μm (middle) and at 70 μm (right), on the same spatial scale. The position of the Cepheid is marked with a star symbol (from Kervella et al., 2009).

N 100 000 au 1 arcmin E scattering that tends to emphasise the this figure only the material that is illumi- the scarcity of similar Cepheid–nebula material located close to the line of sight. nated by RS Pup within 1.8 arcminutes associations, and also confirms that the High degrees of linear polarisation from the star. FORS and EMMI long ex­­ presence of such nebulae is probably not (~ 50%) are observed for several nebular posures show faint nebular extensions far a significant source of photometric bias knots, showing that their position is close beyond this region, at least up to a radius for the calibration of the Cepheid Period– to the plane of the sky (represented in of 3 arcminutes. These distant parts are Luminosity relation. Our determination of blue in Figure 4, lower left). too faint to measure their degree of linear the three-dimensional distribution of the polarisation. dust will also allow us to use the phase of the light echoes to determine unambigu- Origin of the dust nebula This determined mass corresponds only ously the distance of RS Pup. This is a to the light-scattering dust, but does particularly important piece of information As we have determined the geometry of not include the gaseous component, that for this rare, long-period Cepheid, which the dust layer, it is now possible to com- is transparent to light. The typical gas- is a typical example of the stars used to pute the physical distance r between each to-dust mass ratio in the Galaxy is ~ 100. determine extragalactic distances. point in the nebula and the Cepheid (r2 = Z2 The total mass of the nebula, including + R2, Figure 2). Knowing r and the scat- the gas, is therefore approximately 300 As RS Pup illuminates the nebula, part tered light flux, we can deduce the local solar masses. Such a high mass is clearly of its radiation is absorbed by the dust, density of the scattering material at any in­compatible with the scenario that RS which warms up and emits radiation location on the nebula. Figure 4 (lower right Pup created the nebula through mass loss by itself. As the dust is still rather cold panel) shows the resulting density map. (the mass of the Cepheid itself is esti- (~ 40–60 K; Barmby et al., 2011), this

mated to be ~ 13 MA). Most of the dust emission occurs in the infrared domain, Compared to Figure 4 (upper left), the observed in scattered light therefore but it is clearly observable in the Spitzer highest densities do not generally cor­ ap­pears to be of interstellar origin. The images presented in Figure 5. With respond to the brightest parts of the neb- higher density dusty environment in which observations of both the scattered light in ula. This is easy to understand as the RS Pup is presently located could either the visible, and the thermal emission in scattered light flux depends both on the be the remnant of the molecular cloud the mid-infrared domain, together with scattering angle θ and the linear distance from which the star formed, or unrelated the three-dimensional map of the dust r between the star and the dust. A par- interstellar material into which RS Pup is distribution, RS Pup is a particularly ticularly prominent feature is the “ridge” temporarily embedded, due to its motion promising test case for the study of inter- structure visible south of RS Pup. This fil- in the Galaxy. The thin veil geometry of stellar dust properties. amentary dust cloud is located close to the dust layer is probably created by the the plane of the sky, with a slight inclina- radiation pressure from the extremely References tion, as shown in Figure 4 (lower left). bright Cepheid (~ 17 000 LA), that sweeps the interstellar dust away from the star. Barmby, P. et al. 2011, AJ, 141, 42 From the density map, assuming standard Berdnikov, L. N. et al. 2009, Astron. Lett., 35, 406 interstellar dust properties, we estimate Bond, H. E. & Sparks, W. B. 2009, A&A, 495, 371 the total mass of the light-scattering dust Prospects Havlen, R. J. 1972, A&A, 16, 252 to be 2.9 ± 0.9 M . This value should Kervella, P. et al. 2008, A&A, 480, 167 A Kervella, P., Mérand, A. & Gallenne, A. 2009, A&A, be regarded as a lower limit to the true Thanks to our EMMI and FORS observa- 498, 425 mass of the nebula, as we sample only tions, we have established that RS Pup Kervella, P. et al. 2012, A&A, 541, A18 the material in front of RS Pup, while dust did not create the nebula in which it is Sparks, W. B. et al. 2008, AJ, 135, 605 is likely to be present also behind the currently embedded. This peculiar config- Sugerman, B. E. K. 2003, AJ, 126, 1939 Westerlund, B. E. 1961, PASP, 73, 72 plane of the sky. In addition, we include in uration provides a natural explanation to

48 The Messenger 150 – December 2012 Astronomical Science

COSMOGRAIL: Measuring Time Delays of Gravitationally Lensed Quasars to Constrain Cosmology

Malte Tewes1 We live in a golden age for observational Strong lensing time delays Fréderic Courbin1 cosmology, where the Universe seems Georges Meylan1 fairly well described by the Big Bang Gravitational lensing describes the Christopher S. Kochanek2, 3 theory. This concordance model comes deflection of light by a gravitational Eva Eulaers4 at the price of evoking the existence of the field. In the case of a particularly deep Nicolas Cantale1 still poorly known dark matter and even potential well, the phenomenon can Ana M. Mosquera2, 3 more mysterious dark energy, but has the be spectacular: a luminous source in the Ildar Asfandiyarov5 advantage of describing the large-scale background of a massive galaxy (the Pierre Magain4 Universe using only a handful of parame- gravitational lens) can be “multiply im­­ Hans Van Winckel6 ters. Determining these parameters, and aged” and several distorted images of it Dominique Sluse7 testing our assumptions underlying the are seen around this galaxy. This phe- Rathna K. S. Keerthi8 concordance model, requires cosmologi- nomenon is known as “strong gravita- Chelliah S. Stalin8 cal probes — observations that are sen- tional lensing” and has several interesting Tushar P. Prabhu8 sitive tests to the metrics, content and cosmological applications. One of them Prasenjit Saha9 history of the Universe. They include uses the measurement of the “time Simon Dye10 standard candles like Cepheid variable delays” between the multiple images of a stars or Type i a supernovae, standard gravitationally lensed source. rulers like baryonic acoustic oscillations, 1 Laboratoire d’astrophysique, Ecole or involve the measurement of the cos- As illustrated in Figure 1, the different ­Polytechnique Fédérale de Lausanne, mic microwave background as well optical paths to the multiple images of a Switzerland as weak gravitational lensing over large gravitationally lensed source differ in 2 Department of Astronomy, The Ohio areas of sky, to name just a few. length. In addition, the photons propa- State University, USA gate through different depths of the 3 Center for Cosmology and Astroparticle In practice, these probes are all sensitive potential well of the lensing galaxy. As a Physics, The Ohio State University, to different combinations of cosmologi- consequence, the time it takes a photon USA cal parameters, hence making it manda- to reach the observer along each path 4 Institut d’astrophysique et de tory to combine them together in the is different. If the lensed source is photo- ­Géophysique, Université de Liège, best possible way. Comparisons of dif­ metrically variable, like a quasar, the ­Belgium ferent cosmological probes also test their light curves measured for the lensed 5 Ulugh Beg Astronomical Institute, consistency, and allow us to check for image will appear shifted in time by some Academy of Sciences, Tashkent, systematic errors in the measurements. amount called the time delay. This delay Uzbekistan Strong gravitational lensing time delays is directly related to the size of the gravi- 6 Instituut voor Sterrenkunde, Katholieke offer one of these cosmological probes, tational lens system, which essentially Universiteit Leuven, Belgium whose strength has so far been under­ depends on the expansion rate of the 7 Argelander-Institut für Astronomie, estimated due to the lack of adequate Universe, that is, the Hubble constant H0 Bonn, Germany data and tools. (Figure 1). This straightforward “time 8 Indian Institute of Astrophysics,

­Koramangala, Bangalore, India +@QFD4MHUDQRD KNV' K@QFDSHLDCDK@X 9 Institute for Theoretical Physics, ­University of Zürich, Switzerland 10 School of Physics and Astronomy, ­University of Nottingham, UK

2NTQBDPT@R@Q COSMOGRAIL is a long-term pro­ gramme for the photometric monitoring 6S of gravitationally lensed quasars. It makes use of several medium-size tele­ .ARDQUDQ scopes to derive long and well-sampled light curves of lensed quasars, in order +DMRF@K@WX to measure the time delays between the 2L@KK4MHUDQRD GHFG' RL@KKSHLDCDK@X quasar images. These delays directly  relate to the Hubble constant H , with­ 0 Figure 1. Schematic showing out any need for secondary distance how the time delay Δt between calibrations. COSMOGRAIL was initiated two images of a gravitationally in 2004, and has now secured almost a lensed source depends on the decade of data, resulting in cosmologi­ scale of the gravitational lens system, and hence on H0. Illus- 6S cal constraints that are very comple­ tration inspired by Narayan & mentary to other cosmological probes. Bartelmann (1996).

The Messenger 150 – December 2012 49 Astronomical Science Tewes M. et al., COSMOGRAIL

delay method” to constrain H0 had already been proposed by Sjur Refsdal in 1964 (Refsdal 1964), well before the first strongly lensed quasar was even discov- ered by Walsh, Carswell and Weymann in 1979 (Walsh et al., 1979).

The COSMOGRAIL monitoring pro- gramme

Obtaining accurate measurements of time delays is challenging, but has re­cently proved possible. The COSMOGRAIL pro- gramme (COSmological MOnitoring of GRAvItational Lenses) is a long-term photometric­ monitoring programme designed to reach this goal. Initiated and led by the Laboratory of Astrophysics of the École Polytechnique Fédérale de Lausanne, it combines the strengths of medium-size telescopes available for long periods of time, with the collecting power Figure 2. The Swiss 1.2-metre Leonhard Euler Tele- Photometry of the deconvolved images and spatial resolution of the ESO Very scope at the La Silla Observatory, used for several allows the use of data spanning a broad long-term observational programmes, from exoplan- Large ­Telescope (VLT) and the Hubble ets to cosmology. Euler is the main telescope of the range of quality, from 0.8 to 2.0 arcsec- Space Telescope (HST). The medium- COSMOGRAIL collaboration. onds for point source full width at half size telescopes are needed continuously maximum (Tewes et al., 2012b). over several years in order to measure the time delays, while the VLT and HST Light curves and time delay measurement The light curves for the four lensed are needed punctually to obtain deep images of RX J1131−1231 are presented and sharp observations in order to con- With these telescopes, we have gathered in Figure 4, where a time delay of image strain the lens models. Indeed, the meas- almost a decade of photometric data D of about 100 days is striking. With a ured time delays can only be turned into with a temporal sampling of between two closer look, however, the curves do not cosmological inference given accurate and five days depending on the targets. perfectly overlap, even when shifted by lens mass models. As the lensed images of a typical quasar the appropriate delays. Some of the mis- have angular separations on the order matches are conspicuous, on time scales COSMOGRAIL uses several medium-size of an arcsecond, our reduction pipeline of a few weeks to several years. These telescopes to carry out a long-term opti- involves an image deconvolution algor­ discrepancies result from quasar micro- cal photometric monitoring of selected ithm that can carry out photon-noise lensed quasars. Our set of monitoring tel- ­limited photometry of heavily blended escopes includes the Swiss 1.2-metre point sources (e.g., Magain et al., 1998). Figure 3. The quadruply lensed quasar RX Leonhard Euler Telescope at the ESO ­Figure 3 shows an example of such a J1131−1231, seen from space with HST in a colour La Silla Observatory (shown in Figure 2), deconvolution, in the case of the quadru- composite (left; from Claeskens et al., 2006) and the 2-metre Himalayan Chandra Tele- ply lensed quasar RX J1131−1231. The from the ground in the R-band with the Swiss 1.2- metre Leonhard Euler telescope at La Silla (middle). scope (HCT) in India, the 1.5-metre tele- quasar is at a redshift of z = 0.658 The right panel shows the deconvolution of the Euler scope of the Maidanak Observatory whilst the lensing galaxy is at z = 0.295. data, as used for our photometry. (Uzbekistan), and, with a smaller contri- bution, the 1.2-metre Mercator telescope on La Palma (Canary Islands, Spain). In 2010, COSMOGRAIL joined forces with the group of Christopher S. Kochanek 2 ! (Ohio State University, USA) who employs # the 1.3-metre Small & Moderate Aperture & Research Telescope System (SMARTS) - at the Cerro Tololo Inter-American Obser- " vatory in Chile. The resulting collabora- ǥ tion is now the largest quasar lens moni- $ toring programme worldwide. 'TAAKD2O@BD3DKDRBNOD 2VHRR+DNMG@QC$TKDQ3DKDRBNOD$TKDQCDBNMUNKUDC

50 The Messenger 150 – December 2012     Figure 4. R-band light curves for the four lensed  images of the z = 0.658 quasar RX J1131−1231. The 17)l photometry for the 707 epochs is obtained from !  L@F deconvolution photometry. The three colours used  " to display the data points correspond to four differ-  #  L@F

UD ent instruments/telescopes. K@SH

QD 

D 3NS@KDONBGR 2, 132 LDONBGR curve are uncorrelated, as each quasar  $TKDQDONBGR ,DQB@SNQDONBGR image is magnified by different stars of ,@FMHSTC the lensing galaxy.  While quasar microlensing is highly inter- esting on its own and can be used as             ')#l C@X a natural telescope to zoom into the inner parts of quasar accretion discs (for a review, see, e.g., Schmidt & Wambsganss,      2010; Eigenbrod et al., 2008; and also  ESO Release eso08471), it also perturbs­ the time delay measurement. We have therefore devised a set of new numerical

 

UD techniques to measure the time delays @SH

DK and to accurately estimate their uncertain- 

DQ ties, even in the presence of microlensing variability (Tewes et al., 2012a). Applying  these techniques to RX J1131−1231, the

,@FMHSTC delays between the three close images A,  B and C are compatible with being zero, and we measure the delay of image D to be 91 days, with a fractional uncer-           ')#l C@X tainty of only 1.5% (1σ), including system- atic errors (Tewes et al., 2012b). Our monitoring data, deconvolution photome- lensing: individual stars of the lensing (­magnification) yields a change in total try technique and “curve shifting” meth- ­galaxy, in the foreground of a given qua- flux, since gravitational lensing conserves ods are now all sufficiently tested and sar image, act as additional gravitational ­surface brightness. The stars move rela- accurate that the uncertainties in the time lenses and further distort and magnify tive to the line of sight on orbits within the delay measurements no longer dominate the latter. This effect is illustrated in Fig- galaxy and the resulting fluctuating mag- the total error budget of the cosmological ure 5. While the image distortions re- nifications significantly perturb the light inferences, as has long been the case. main undetectable even at high spatial curves of the quasar images. The micro- reso­lution, the apparent increase in size lensing perturbations seen in each light Follow-up observations for accurate lens models Y   Y   RNTQBD KDMR While medium-size telescopes are used ŠKHFGSC@XR to measure the delays, VLT spectroscopy of the lensing galaxy and of other mas- sive intervening galaxies along the line of sight is a key step in building the models needed to interpret the delays. In parallel,

Figure 5. Toy model of quasar microlensing by stars of a galaxy at z = 0.3, which acts as a gravitational lens on a quasar at z = 0.6. The represented field of view is only 20 micro-arcseconds on a side. At such a huge spatial resolution, we clearly see the original LHBQN@QBRDB quasar image (left) distorted and magnified by micro- lensing due to solar-mass stars, represented by the + symbols (right). With real observations, we can 4MKDMRDCPT@R@Q ,@BQNLHBQNKDMRDCHL@FD only observe the integrated flux of this scene.

The Messenger 150 – December 2012 51 Astronomical Science Tewes M. et al., COSMOGRAIL

deep HST or ground-based adaptive results were then published without any ing surveys, notably in the southern hem- optics imaging is crucial to reveal the further modification. The combination of isphere, the time delay technique has a ­Einstein rings formed by the host galax- RX J1131−1231 with only one other qua- promising future in providing stringent ies of the lensed quasars. These highly sar lens — also performed in Suyu et al. and independent constraints on cosmol- distorted extended images, if bright (2012) — further reduces these uncer- ogy. In the mean time, the ~ 20 currently enough, strongly constrain the radial tainties, as all known systematic errors monitored COSMOGRAIL targets and mass profile of the lensing galaxy, and are under control. their follow-up with present-day facilities therefore are a key ingredient in linking will already lead to results that are highly the delay measurements to cosmology. competitive with much more expensive Prospects cosmological probes. By building a state-of-the-art lens model of RX J1131−1231, Suyu et al. (2012) COSMOGRAIL illustrates very well the show that our delays of the single lens complementarity between astronomi- References RX J1131−1231 already lead to impressive cal facilities and combines many tech- Claeskens, J.-F. et al. 2006, A&A, 451, 865 constraints. The resulting cosmological niques of optical astronomy: (1) medium- Eigenbrod, A. et al. 2008, A&A, 490, 933 parameter inference depends on the size telescopes to carry out the long- Magain, P., Courbin, F. & Sohy, S. 1998, ApJ, assumed cosmological model. For the term photometric­­ monitoring; (2) HST or 494, 472 case of a spatially flat universe in which VLT with adaptive optics to constrain Refsdal, S. 1964, MNRAS, 128, 307 Schmidt, R. W. & Wambsganss, J. 2010, Gen. Rel. the behaviour of dark energy is para- the lens models using high ­resolution and Gravit., 42, 2127 metrised by its equation-of-state parame- imaging; (3) deep VLT spectroscopy to Suyu, S. et al. 2012, arXiv:1208.6010 ter, w, the combination of RX J1131−1231 measure redshifts and to constrain the Tewes, M. et al. 2012a, arXiv:1208.5598 with the WMAP7 dataset gives: H = dynamical mass model. In the future, Tewes, M. et al. 2012b, arXiv:1208.6009 0 Walsh, D., Carswell, R. F. & Weymann, R. J. 1979, +5.8 −1 −1 80.0 –5.7 km s Mpc , Ωde = 0.79 ± 0.03, JWST and the E-ELT will allow the 2D Nature, 279, 381 +0.17 and w = –1.25–0.21. Interestingly, this velocity field of the lensing galaxies to be analysis was carried out with a purposely mapped and Einstein rings to be imaged “blind” approach. The absolute inferred with exquisite quality, especially using Links values of the cosmo­logical parameters image deconvolution techniques. 1 ESO release on microlensing in the Einstein Cross: were revealed only once all members of http://www.eso.org/public/news/eso0847/ our collaboration were satisfied with their With the large number of lensed quasars part of the data analysis, and these that remain to be discovered in forthcom- ESO/P. Grosbøl ESO/P.

Near-infrared representative colour image of the nearby prototypical barred spiral galaxy NGC 1300 taken with HAWK-I on the VLT. The filters used wereY (shown here in dark blue), J (in light blue), H (in green), and K (in red). This galaxy of type SB is at a distance of about 19 Mpc, has a central supermassive black hole and the spiral arms show many young clusters. The image size is about 6.4 arcminutes. More details can be found in Release eso1042.

52 The Messenger 150 – December 2012 Astronomical Science

Breaking Cosmic Dawn: The Faintest Galaxy Detected by the VLT

Maruša Bradač1 after the Big Bang when early light z > ~ 7 gal­axies using the dropout tech- Eros Vanzella2 sources produced enough energetic nique (Steidel et al., 1996), both in Nicholas Hall1 ­photons to ionise the neutral hydrogen, blank fields (the Hubble Ultra-Deep Field Tommaso Treu3 making the Universe transparent to visi- [HUDF] and the Cosmic Assembly Adriano Fontana4 ble light. This era is referred to as reioni- ­Near-infrared Deep Extragalactic Legacy Anthony H. Gonzalez5 sation and is also the era of the formation Survey [­CANDELS]; e.g., Bouwens et al., Douglas Clowe6 of the first galaxies. But when exactly 2012), and behind galaxy clusters (e.g., Dennis Zaritsky7 did reionisation occur and how long did Hall et al., 2012). One of the most obvious Massimo Stiavelli8 it last? What were the sources responsi- limitations of the dropout technique, how- Benjamin Clément7 ble for ionising the neutral gas? Was it ever, is that unambiguously confirming the first galaxies? Now, for the first time, the object’s redshift usually requires we can peer far enough into space to spectroscopic follow-up. This is hard to 1 Department of Physics, University of detect these galaxies spectroscopically do for the typically faint high-z sources. California, Davis, USA and answer these questions. 2 INAF, Osservatorio Astronomico di However much more important than the ­Trieste, Italy Observations of galaxies at these early redshift confirmation, spectroscopy 3 Department of Physics, University of times are challenging, not only due to ­provides information on properties of the California, Santa Barbara, USA the large distance to these objects, but interstellar and intergalactic media (ISM 4 INAF, Osservatorio Astronomico di also due to their lower luminosity (gal­ and IGM). In particular, Lyman-α emission Roma, Monteporzio, Italy axies had fewer stars when they first from sources close to the reionisation 5 Department of Astronomy, University of formed). The quest to discover the most era is a valuable diagnostic, given that it Florida, Gainesville, USA distant (i.e., first) galaxies has advanced is easily erased by neutral gas within 6 Department of Physics & Astronomy, rapidly in the last decade. With the help and around galaxies. The observed Ohio University, Athens, USA of a galaxy cluster acting as a cosmic strength of Ly-α in distant galaxies is a 7 Steward Observatory, University of ­telescope and magnifying the back- gauge of the time when reionisation was ­Arizona, Tucson, USA ground Universe, we have observed the completed (Robertson et al., 2010). Fur- 8 Space Telescope Science Institute, faintest galaxy ever detected spectro- thermore, we expect Ly-α Emitters (LAEs) ­Baltimore, USA scopically at these extremely large dis- to be predominantly dust-free galaxies;­ tances. It was detected using the FORS2 hence their numbers should increase with spectrograph on the Very Large Telescope redshift until the state of the IGM becomes Astronomers have been debating the (VLT). With an extremely long ex­­­posure neutral, at which point their numbers origin of galaxies for centuries and time (16 hours on a mask, a total of should decline. the timeline of the evolution is now well 22 hours of observing time) and assisted established. However, despite the by nature’s own telescope (The Bullet A powerful way to detect emission lines ­success of galaxy formation models, Cluster) we were able to push to the limits from faint sources is to use galaxy clus- some questions remain largely unan­ of the light-gathering power of the VLT ters as cosmic telescopes (e.g., Treu, swered. Chief among them is how the which allowed us to detect Lyman-α [2010] for a recent review). Gravitational first galaxies formed. When the Uni­ emission from this “normal” (i.e., not ultra- lensing magnifies solid angles while pre- verse was in a highly opaque state, luminous) galaxy (Bradač et al., 2012). serving colours and surface brightness. these first galaxies most likely cleared Thus, sources appear brighter than in the the cosmic fog and broke the cosmic absence of lensing. The advantages of dawn. However, there are large uncer­ Beyond simple counting cosmic telescopes are that we can probe tainties as to how this transition oc­ deeper (due to magnification), sources curred and what the exact role of the Detection of high-redshift galaxies is are practically always enlarged and iden- first galaxies was. Using galaxy clusters ­performed by searching for the redshifted tification is further eased if sources are as cosmic telescopes that magnify Lyman break using broadband photo­ multiply imaged. Typically, one can gain background objects, we were able to metry (Steidel et al., 1996). These so- several magnitudes of magnification, thus detect hydrogen emission from a galaxy called Lyman Break Galaxies (LBGs, see enabling the study of intrinsically lower at a redshift of z = 6.740 ± 0.003 using e.g., Vanzella et al., 2009) are the best luminosity galaxies that we would other- FORS2 on the VLT. To date, this is studied and the largest sample of galax- wise not be able to detect with even the the faintest galaxy with a successfully ies at redshifts z > ~ 5. One can identify largest of current telescopes. measured spectrum and as such z ≈ 5 objects by their non-detection in an important beacon for cosmic dawn. the V-band and blueward: such objects are referred to as V-band dropouts. The combined power of VLT and the ­Similarly, objects at z ≈ 6 are associated “Silver­ Bullet” Cosmic dawn through cosmic telescopes with i-band non-detection, z ≈ 7–8 with z-band, and z > ~ 8 objects would be Our targets were selected from deep The cosmic Dark Ages are thought to observed as J-band dropouts. Substan- Ad­vanced Camera for Surveys (ACS) and have ended around 500 million years tial progress has been made in detecting Wide Field Camera 3 (WFC3) data, both

The Messenger 150 – December 2012 53 Astronomical Science Bradač M. et al., The Faintest Galaxy Detected by the VLT

on the Hubble Space Telescope (HST). Out of the ten z-band dropout candidates Breaking cosmic dawn Ten z-band dropouts were found by targeted, we detected an emission line at Hall et al. (2012). The aim of the VLT pro- 9412 Å with 5σ significance (see Figure 1) While this work presents only a single gramme 088.A-0542 (PI Bradač) was in one target. The line is detected in two spectroscopic detection at z > 6.5, to target all these extraordinary targets ­different FORS2 masks and is broader it nonetheless probes a very important with the FORS2 spectrograph. ­Ordi- than cosmic rays or residuals due to sky region of parameter space. The intrin- narily the hope of detecting any of these subtraction; hence we are confident that sic (unlensed) line flux of this object is sources even with a programme of the line is not an artefact (see Figure 2). ~ 2−3 times fainter than the, until now, 22 hours would be impossible, as their No other emission lines are detected in faintest spectroscopic detection of an intrinsic magnitudes are H > 27 AB mag. the spectrum (7700–10000 Å); if the LAE at z ~ 7 (Schenker et al., 2012). Its However with the help of magnification object were at lower redshift one would intrinsic H(160W)-band magnitude is int from the Bullet Cluster, which is one of have expected detections of several mH(160W) = 27.57 ± 0.17, corresponding to the best cosmic telescopes (due to its lines. Based on this lack of other lines an intrinsic luminosity of 0.5 L* at this red- large mass and elongation, the magnifi- and on the spectral energy distribution fit shift (see Table 1). cations are large), the observed magni- using imaging, we exclude other alter­ tudes of these ten sources are H = 25–27 native explanations and conclude that But more important than the record AB mag. Of course, this does not make the line is most likely Ly-α at z = 6.740 ± breaking is the fact that these sources the observing easy per se! 0.003. are excellent beacons of cosmic

Figure 1. A distant source observed from when the Universe was less than 10% of its current age. The object was found behind the Bullet Cluster. The top row shows an image of the cluster (from HST and WFC3), and a zoom-in on the source in a colour composite from an optical image and an infrared image. The bottom row shows a confirmation spec- trum (from FORS2) of the object (sky emission above, object spectrum with Ly-α emission below). Colour Optical Composite 800–950 nm Infrared 950–1600 nm

SKY 900 nm 980 nm

MASK 1+2 Lyα

Figure 2. Upper: 2-D spectrum of the dropout galaxy (sky emission above, spectra from individual masks MASK 1 below). Lower: 1-D spectrum of the object. The sky spectrum has been rescaled by a factor of 300 and offset for display purposes, and the regions where MASK 2 skylines are more intense have been marked with transparent vertical bars. Strong residuals in the sky MASK 1+2 subtraction are evident and correspond to the more intense sky lines. Note that the detected line is broader than residuals of sky subtraction, confirming –19 Ly the reality of the feature. ) 5 × 10 α /Å 2 spectrum m

/c 0 /s rg (e )

λ –19 f( –5 × 10 sky

9 000 9200 9400 9600 9800 Wavelength (Å)

54 The Messenger 150 – December 2012 ­reionisation. Measuring the rest frame R.A. 104.63015 Table 1. Imaging and spectroscopic properties of z -band dropout #10 equivalent width (EW) distribution of LAEs Dec. –55.970482 850 from Hall et al. (2012). as a ­function of redshift and luminosity mH160W 26.37 ± 0.16 is a powerful tool to study reionisation. mJ110W 26.5 ± 0.3

The EW distribution changes with redshift (J110W — H160W) 0.10 ± 0.15 and source luminosity. Simulations sug- (z850LP — J110W ) 1.57 ± 0.68 a gest that reionisation is the key factor mV606 > 28.75 (texp = 2336s) driving this trend (Dayal & Ferrara, 2012), mi775W > 28.60 (texp = 10150s) because, unlike continuum photons, the mI814W > 29.00 (texp = 4480s)

Ly-α photons that escape the galactic mKs > 26.65 (texp = 3.75hr) environment are attenuated by the neutral μ 3.0 ± 0.2 hydrogen in the IGM. With a measure- int +0.17 mH(160W) 27.57 –0.17 ment of the EW distribution in LAEs we can therefore help distinguish between λ 9412 Å effects of ISM dust and neutral IGM z 6.740 ± 0.003 b –17 2 and study the epoch of reionisation (see f (0.7 ± 0.1 ± 0.3) × 10 erg/s/cm f 3.3+ 1.0 × 10–20 erg/s/cm2/Å also Treu et al., 2012). λ,c – 0.8 f int (0.23 ± 0.03 ± 0.10 ± 0.02) × 10–17 erg/s/cm2 f int 1.1+ 0.4 × 10–20 erg/s/cm2/Å Our source is the faintest (in line flux) λ,c – 0.3 W (Ly- ) 30+12 Å detected thus far and is only the second rest a – 21 firm spectroscopic detection of a sub-L* source at z > 6.5 (the other example is also a lensed galaxy at z = 7.045 discov- Extreme Imaging Reaching Out to Acknowledgements ered by Schenker et al. [2012]). z > ~ 7) will open up new parameter Support for this work was provided by NASA space and will allow us to study the prop- through HST-GO-10200, HST-GO-10863, and HST- erties (e.g., star formation rates and GO-11099 from STScI, from ASI–INAF, from the NSF, Future is made bright by gravitational ­stellar masses) of a large number of gal- Sloan and Packard Foundations as well as KITP. lensing axies at z ~ 7 for the first time. The ­presence (or absence) of an established References With future observations of dropout stellar population will be measured in objects magnified by cosmic telescopes the targets and these findings will allow Bouwens, R. J. et al. 2012, ApJ, 754, 83 we will further increase the sample. As us to identify the dominant sources of Bradač, M. et al. 2012, ApJ, 755, L7 Dayal, P. & Ferrara, A. 2012, MNRAS, 421, 2568 noted above, measuring the EW distri­ the bulk of ionising photons necessary to Hall, N. et al. 2012, ApJ, 745, 155 bution of LAEs as a function of redshift drive reionisation. McLean, I. S. et al. 2010, SPIE, 7735, and luminosity is a very powerful tool to Robertson, B. E. et al. 2010, Nature, 468, 49 study reionisation, because the latter is Furthermore, in the local Universe, Schenker, M. A. et al. 2012, ApJ, 744, 179 Steidel, C. C. et al. 1996, ApJ, 462, L17 likely to be the key factor driving the trend star formation is associated with mole­ Treu, T. 2010, ARA&A, 48, 87 of EW and luminosity. The main missing cular gas, and therefore to understand Treu, T. et al. 2012, ApJ, 747, 27 observational ingredient is a measure- star formation properties we would like to Vanzella, E. et al. 2009, ApJ, 695, 1163 ment of the EW distribution for both lumi- trace molecules in the cold ISM of high nous and sub-L* galaxies at the red- redshift galaxies. ALMA is opening a new shifts of reionisation; future surveys and window for this endeavour. It is designed facilities will achieve exactly that (e.g., to trace molecular gas in galaxies up to X-shooter on VLT and the new spectro- z ~ 5 in the brightest cases. With the graph ­MOSFIRE on Keck; see McLean assistance of gravitational lensing, how- et al., 2010). ever, these limits can be pushed to the redshifts near reionisation. ALMA’s Perhaps even more importantly, however, incredible resolution can also be further we will also add the wavelength cover- improved with lensing, giving us access age to the observations. A first major to the sub-kpc regime. This will allow improvement will be performed with deep us to characterise the spatial distribution Spitzer observations. There is a large and kinematics of the cold ISM in these Exploration Science programme extremely high redshift, but not ultra- approved for Spitzer Cycle 9. The pro- luminous galaxies, something that would gramme (Spitzer UltRaFaint SUrvey - not have been possible without the help SURF’S Up: Cluster Lensing and Spitzer of gravitational lensing.

The Messenger 150 – December 2012 55 Astronomical Science

Early ALMA Science Verification Observations of Obscured Galaxy Formation at Redshift 4.7

Jeff Wagg1, 2 observations are providing sensitive, far-infrared lines like the 157.7 μm [C ii] Tommy Wiklind3 unobscured images of the formation of line. This emission is believed to trace Chris Carilli4 massive galaxies. Observations of photon-dominated regions and the cold Daniel Espada5 BR1202-0725 at z = 4.7 are described neutral medium, and has now been stud- Alison Peck3, 6 as an example. ied by the Infrared Space Observatory Dominik Riechers7, 8 (ISO) and Herschel in large samples of Fabian Walter9 star-forming galaxies and AGN in the Al Wootten6 Understanding how galaxies acquire nearby Universe (e.g., Genzel & Cezarsky, Manuel Aravena2 their gas and convert that gas into stars 2000; Sargsyan et al., 2012) to provide Denis Barkats3 at high redshift represents one of the an unobscured probe of star formation Juan Cortes3 ­outstanding problems in galaxy forma- activity. [C ii] line emission is being de­­ Richard Hills1, 3 tion. Studies of atomic hydrogen emis- tected in high-redshift galaxies between Jacqueline Hodge9 sion at long radio wavelengths are limited z ~ 1 and 7 (e.g., Venemans et al., 2012), Violette Impellizeri3 to the very nearby Universe, while cold confirming its usefulness as a tool to Daisuke Iono5 molecular gas may be probed at millime- study star formation and the kinematics Adam Leroy6 tre and centimetre wavelengths through of distant galaxies. Sergio Martin2 observations of redshifted CO line emis- Mark Rawlings3, 6 sion out to the epoch of reionisation (e.g., Roberto Maiolino1 Wang et al., 2010). Major advances in our ALMA commissioning observations Richard G. McMahon9 understanding of the cold gas content in Kim S. Scott6 the most distant galaxies can be attrib- Located at an elevation of 5000 metres in Eric Villard3 uted to interferometers like the Plateau the Chilean Atacama Desert, ALMA is Catherine Vlahakis3 de Bure Interferometer (PdBI), the Com- the largest submillimetre and millimetre bined Array for Research in Millimeter- wavelength telescope in the world. Part wave Astronomy (CARMA) and the Jansky of the commissioning and science veri­ 1 Cavendish Laboratory, University of Very Large Array (JVLA). The Atacama fication phase involves demonstrating the Cambridge, UK Large Millimeter/submillimeter Array efficacy of various calibration-related 2 ESO (ALMA) complements these facilities by properties of the array by repeating ob­­ 3 Joint ALMA Observatory, Santiago, providing an order of magnitude increase servations made with other facilities (Hills Chile in shorter submillimetre wavelength et al., in prep.). One of the top-level sci- 4 National Radio Astronomy Observatory, ­sensitivity to cold gas and dust in galax- ence goals for ALMA is to detect far- Socorro, USA ies over a broad range in redshift. Inter- infrared (FIR) line emission from ionised 5 National Astronomical Observatory of ferometric observations at these higher gas in star-forming galaxies redshifted Japan, Tokyo, Japan ­frequencies are necessary to resolve to submillimetre wavelengths, and so in 6 National Radio Astronomy Observatory, spatial variations in the cold dust proper- order to demonstrate that this is possible Charlottesville, USA ties and characteristics of atomic and we observed the [C ii] line and dust 7 Dept. of Astronomy, California Institute molecular gas in young galaxies, which ­continuum emission in BR1202-0725 at of Technology, Pasadena, USA will ultimately shed light on how they z = 4.7. 8 Cornell University, Ithaca, USA formed their stars early on. 9 Max Planck Institute for Astronomy, BR1202-0725 had previously been Heidelberg, Germany The first single-dish, submillimetre wave- observed with the Submillimeter Array 10 Institute of Astronomy, University of length continuum observations of cold (SMA) on Mauna Kea (Iono et al., 2006), Cambridge, UK dust in high-redshift quasars and mas- and is composed of two intrinsically sive starburst galaxies demonstrated that ­luminous and (presumably) massive gal- the formation of these objects can be axies, both rich in molecular gas and Roughly half the star formation in the accompanied by large quantities of dust dust (Omont et al., 1996). One of the pair young Universe is thought to have that may be heated by star formation is an optically luminous quasar, while been heavily obscured by dust and and/or active galactic nucleus (AGN) ac­­ the other shows no signs of AGN activity molecular gas. A new suite of facilities tivity, leading to high far-infrared lumi­ and is undetected in sensitive optical and experiments operating at submilli­ nosities for the most extreme objects and infrared images. At z = 4.7, the [C ii] metre through to centimetre wave­ (e.g., Omont et al., 1996). These early line is redshifted into the 340 GHz lengths is providing astronomers with studies helped to motivate the need for (Band 7) receiver window where ALMA the ability to study galaxies whose star higher spatial resolution imaging with provides a unique increase in sensitivity formation and AGN activity would be facilities like ALMA, which will be used to over other telescopes, even with only partially invisible to optical telescopes. constrain the source of the dust heat- the sixteen­ 12-metre antennas that were The most sensitive of these new in­ ing. Fuelled by high molecular gas frac- typically available early in 2012. The struments is ALMA. Even with only a tions (Daddi et al., 2010; Tacconi et al., ­previous SMA observations of [C ii] line subset of the final number of 12-metre 2010), star formation in young galaxies is emission represented the only resolved antennas operational, the first ALMA also accompanied by strong emission in observations of weak and broad, high

56 The Messenger 150 – December 2012 redshift line and dust continuum emission Figure 1. 10 by 10 arcsecond ALMA at these frequencies, making this a 340 GHz (Band 7) image of thermal dust continuum emission in BR1202- unique target for ALMA science verifica- 0725, a system composed of at least tion. These and other commissioning two FIR luminous galaxies (a quasar data have been made public to the com- host galaxy and a heavily obscured munity who are encouraged to use them starburst) that existed 1.3 billion years 1 after the Big Bang. The faint submilli- for training or scientific purposes . metre source below and to the right of BR1202-0725 South may also be part of the same group of galaxies. Gas and dust in BR1202-0725 The synthesised beam size is 0.9 by 1.3 arcseconds. Band 7 ALMA observations toward BR1202-0725 were made in January 2012 using seventeen 12-metre diameter ALMA antennas for 25 minutes of total on-source observing time (Wagg et al., 2012). The 340 GHz continuum image with a synthesised beam size of 1.3 × 0.9 arcseconds is shown in Figure 1, and even with such a short integration time this map is already an order of magnitude more sensitive than the previous SMA observations. The northern and southern dynamical interaction, then it is likely that and have been observed in a quasar host components of BR1202-0725 are sepa- they will evolve into a massive galaxy with galaxy that existed about 850 million 11 rated by ~ 4 arcseconds, which roughly a stellar mass that could grow to 10 MA. years after the Big Bang (Maiolino corresponds to 25 kpc at this redshift, et al., 2012). The large width of the [C ii] while the positions of the sources in the We also detect the [C ii] line emission with line emission in the northern component ALMA map are consistent with SMA and high significance in the two brightest is similar to what was observed with PdBI observations (Omont et al., 1996; members of the BR1202-0725 system Iono et al., 2006; Salomé et al., 2012). (Figure 2). These are some of the most These ALMA data reveal a third faint sub- sensitive spectra of this line obtained in Figure 2. [C ii] line emission in BR1202-0725 North millimetre counterpart, whose redshift high redshift galaxies, and the line profile and South at z = 4.69 after subtraction of the contin- is uncertain, but which may be associated for the quasar is even suggestive of the uum emission. The spectra have a typical rms of with a Lyman-a emitter at the same red- presence of an outflow of ionised carbon. ~ 2 mJy per ~ 28 km/s channel. The high signal-to- shift as the BR1202-0725 system (Hu et Such outflows of gas from the central noise of these spectra reveal how the starburst ­galaxy to the north has a larger [C ii] line luminosity al., 1996). If all three objects lie at the AGN can potentially quench star forma- than the quasar host galaxy, while both have similar same redshift and are in the process of a tion in the interstellar medium of galaxies FIR luminosities. Figures from Wagg et al. (2012).

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The Messenger 150 – December 2012 57 Astronomical Science Wagg J. et al., ALMA Observations of Obscured Galaxy Formation at Redshift 4.7

the SMA, while the small [C ii]-to-FIR Prospects The results presented here are due to the luminosity ratio is lower in the quasar hard work and dedication of many people than the starburst, which is consistent These science verification observations from around the world, and we are grate- with what is observed in AGN and with ALMA demonstrate the ability to ful to everyone who has made ALMA a starbursts in the nearby Universe and detect weak line emission from high red- reality. z ~ 1 (Stacey et al., 2010; Sargsyan et al., shift galaxies at submillimetre wave- 2012). lengths. Higher spatial resolution ALMA [C ii] line observations will inevitably reveal References Recent observations of high-J CO lines the dynamical structure of the BR1202- Daddi, E. et al. 2010, ApJ, 713, 686 and millimetre wavelength dust cont­ 0725 galaxy merger, and determine if the Genzel, R. & Cesarsky, C. J. 2000, ARA&A, 38, 761 inuum emission from the PdBI confirm third continuum source is at the same Hu, E. M., McMahon, R. G. & Egami, E. 1996, ApJL, the complex nature of the BR1202-0725 redshift as the two more luminous mem- 459, L53 system (Salomé et al., 2012). The CO bers. Further observations of redshifted Iono, D. et al. 2006, ApJL, 645, L97 Maiolino, R. et al. 2012, MNRAS, 425, L66 data agree with the ALMA [C ii] observa- FIR line emission in massive galaxies Nagao, T. et al. 2012, A&A, 542, L34 tions in that the starburst galaxy exhibits have now been conducted as part of the Omont, A. et al. 1996, Nature, 382, 428 broader linewidths in both species than early-science operations phase and both Salomé, P. et al. 2012, A&A, 545, A57 Sargsyan, L. et al. 2012, ApJ, 755, 171 those observed in the quasar. The CO [C ii] and the weaker [N ii] 205 µm line Stacey, G. J. et al. 2010, ApJ, 724, 957 emission appears to be extended from emission have been detected (Nagao et Swinbank, M. et al. 2012, arXiv:1209.1390 the quasar, but is not coincident with the al., 2012; Swinbank et al., 2012; de Tacconi, L. J. et al. 2010, Nature, 463, 781 faint 340 GHz continuum source de­­ Breuck et al., in prep.). Taken together, Venemans, B. P. et al. 2012, ApJL, 751, L25 tected by ALMA, and all of the data are the early results from ALMA provide a Wagg, J. et al. 2012, ApJL, 752, L30 Wang, R. et al. 2010, ApJ, 714, 699 consistent with this system representing preview of how this enormous increase in a merger of gas-rich galaxies that existed submillimetre wavelength sensitivity will 1.3 billion years after the Big Bang. lead to a transformation in our under- Links standing of the gas content of high-red- 1 Access to ALMA Verification data:http:// ­ shift galaxies. almascience.eso.org/alma-data/science-veification ALMA (ESO/NAOJ/NRAO); ESO/Y. Beletsky

ALMA Band 3 Science Verification image of the nearby galaxy Centaurus A (NGC 5128) in CO(1-0) emission overlaid on an NTT/SOFI near-infrared image. The CO emission is colour coded by the radial velocity of the molecular gas showing evi- dence for rotation of the disc around the centre of the galaxy. The galaxy nucleus, visible in the SOFI image, hosts a central massive black hole. See Release eso1222 for more details.

58 The Messenger 150 – December 2012 Astronomical Science

Science Verification Datasets on the ALMA Science Portal

Leonardo Testi1 accompanied by data reduction scripts inner one square arcminute was mapped Martin Zwaan1 and a set of sample images or data- in the CO(2-1) line by Espada et al. (2009) Catherine Vlahakis2 cubes. For some of the SV data releases, using the Submillimeter Array (SMA). Stuartt Corder2 detailed data reduction guides have With ALMA, a large mosaic of pointings been made available to explain the data was used to map the three-dimensional reduction procedures for the various structure of the gas disc. The CO(2-1) 1 ESO modes step by step. Here, we illustrate velocity field overlaid on a near-infrared 2 Joint ALMA Observatory, Chile some of the released datasets and invite image produced by the NTT is shown in interested users to visit the Science the figure on p. 58. ­Portal webpages to download the data- We summarise the ALMA Science sets in which they may be interested. Another large mosaic was taken in Band ­Verification datasets released over the 3 to map the CO(1-0) gas in the grand- past year, the ALMA capabilities that design, nearly face-on spiral galaxy M100 were demonstrated and how the ALMA Molecular gas in galaxies in the Virgo cluster, at a distance of results compare with previous obser­ ~ 16 Mpc. Molecular gas in this galaxy is vations. Some new scientific results The radio-quiet quasar BR1202-0725, abundant in the centre and along the that have been produced using the at a redshift z = 4.69, was one of the ear- ­spiral arms. The entire gas disc was pre- public Science Verification datasets are liest detections of molecular gas at very viously mapped at 6-arcsecond resolu- summarised and an overview of the high redshift (z > 2). Previous interfero- tion using the Berkeley–Illinois–Maryland capabilities that will be demonstrated metric observations detected CO(5-4) Association (BIMA) millimetre interfer­ with future Science Verification obser­ emission and dust continuum in two ometer (Helfer et al., 2003). The ALMA SV vations is provided. compact sources separated by ~ 4 arc- observations consisted of 47 pointings seconds (Omont, 1996). This turned and cover a region of 5 by 5 arcminutes, out not to be due to gravitational lensing, with an angular resolution of 3 arcsec- ALMA Science Verification (SV) is the and instead the southern component onds. The CO map recovers all the struc- process used to demonstrate that ALMA has been established to be associated tures seen by Helfer et al. (2003). Further- is capable of producing data of the with a quasar, whilst the northern compo- more, ALMA detects continuum emission ­quality required for scientific analysis. nent is an optically faint submillimetre at the centre of the galaxy, which was The SV process is part of the Commis- ­galaxy (SMG). In ALMA Band 7 SV data not found in previous observations. Fig- sioning and Science Verification (CSV) on this field, [C ii] 158 μm emission is ure 1 shows the impressive spiral struc- effort within ALMA and is carried out by clearly detected from both components. ture seen in CO by ALMA. the ALMA CSV team with data reduc- The brightness of [C ii] makes this line tion support from the ALMA Regional ideal for tracing the kinematics of galaxies Centres. ALMA Science Verification data and for identifying possible outflows. The The Galactic Centre are made publicly available on the ALMA fact that ALMA SV observations detect Science Portal as soon as satisfactory this line at such high significance in only The Galactic Centre, Sagittarius A* observations and data reduction are 25 minutes on-source integration time, (Sgr A*), is a very interesting ALMA target achieved. The community is encouraged using only 17 main array antennas, clearly for the purpose of studying the interac- to use these datasets to familiarise demonstrates the power of ALMA for the tion between a supermassive black hole ­themselves with the ALMA capabilities study of line emission from high-redshift and its surrounding environment. ALMA and data reduction procedures, as well objects. A study using these SV data on SV data were taken towards Sgr A* both as to publish interesting new science BR1202-0725 was published­ by Wagg et in Band 3 and Band 6 with the aim of results that they may obtain from analys- al. (2012); see also the article on p. 56. imaging the hydrogen recombination line ing the datasets. Detailed information emission. The Band 6 data were taken in on the ALMA SV process can be found Centaurus A is a massive elliptical galaxy a seven-point mosaic, while the Band 3 on the Science Portal SV page1. and is one of the best-studied, as well observations consisted of a single point- as the nearest (~ 3.8 Mpc), radio galaxies ing. The mini-spiral structure is clearly About a year ago, we provided an initial in the sky. It is characterised by a strong visible in both recombination line maps account of the status of ALMA SV in Testi dust lane seen in visible light, oriented (Figure 2), and these maps agree very & Zwaan (2011). At that time, few initial along the galaxy minor axis, which har- well with the Combined Array for Research 8 datasets demonstrating single-field inter- bours ~ 4 × 10 MA of molecular gas. in Millimeter-wave Astronomy (CARMA; ferometry with a small set of antennas This feature, together with the strong H41α; Shukla et al., 2004) and SMA had been fully processed and released. radio emission, indicates that Centaurus (H30α; Zhao et al., 2011) observations. Now, a broad range of datasets is avail­ A is the result of a collision between a able on the ALMA Science Portal2. The giant elliptical galaxy and a smaller gas- datasets cover a variety of science tar- rich spiral galaxy. High spectral resolution Star-forming regions gets and ALMA modes, including ALMA SV data were taken in Band 6 in ­mosaics, high frequency observing and order to map the extended CO(2-1) emis- The study of protoplanetary discs is one spectral survey. All data releases are sion along the dust lane. Previously, the of the main science goals of ALMA and

The Messenger 150 – December 2012 59 Astronomical Science Testi L. et al., Science Verification Datasets on the ALMA Science Portal

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Figure 1. Intensity-weighted CO(1-0) velocity field Figure 2. Hydrogen recombination line emission of the grand-design spiral galaxy M100, with total toward SgrA*. The map shows the integrated intensity contours overlaid. ­emission map of the H30α line seen in the inner 30 square arcsecond region of the Galactic Centre. we had foreseen from the beginning a two main components of the multiple rate studies based on these data have large number of external users wishing to system. This was the first ALMA Band 9 already been published (Fortman et al., obtain data on these objects. SV data dataset to be publicly released and is 2012; Galvan-Madrid et al., 2012; Hirota on two very well-known protoplanetary accompanied by an extensive data reduc- et al., 2012; Niederhofer et al., 2012; discs — TW Hya and HD163296 — have tion guide. The data have been used and Zapata et al., 2012). The results span been released. TW Hya datasets have by separate groups to study the gas kine- the range of topics from comparison already been presented in Testi & Zwaan matics around the protostars (Pineda with laboratory spectra, to the study of (2011). HD163296 is a young interme­diate- et al., 2012) and to detect, for the first water masers, SiO isotopologues in the mass star known to host a protoplanetary time, in a solar-mass protostellar system, outflow and radio hydrogen recombina- disc and has been extensively ­studied a simple form of sugar, glycolaldehyde. tion line emission. at millimetre wavelengths (Mannings­ & This is a key pre-biotic molecule which is Sargent, 1997; Isella et al., 2007; Qi et al., found to be present in the disc surround- 2011). SV observations demonstrated ing the young protostars and infalling Future SV observations one of the basic multi-spectral resolution onto the planet formation regions of the ALMA capabilities, where lines and disc (see Figure 4, Jorgensen et al., 2012 At the time of writing, ALMA SV is now ­continuum can be ob­­served using a com- and ESO release eso1234). moving into demonstrating the capabili- bination of four separate spectral win- ties for Cycle 1 and beyond. The details dows with different bandwidth and spec- The Orion KL hot core was observed in of the planning and the targets for SV are tral resolution. The released ALMA Band 6 as a spectral survey. This region, discussed in detail on the Science Portal Band 6 and Band 7 observations cover extensively studied at all wavelengths, SV page2. Here, we provide a summary the continuum at 1.3 and 0.85 mm as including the millimetre and submillimetre, of the areas that will be the subject of SV well as several emission lines from the was the obvious choice for such an SV in the near future and for which external isotopes of CO and HCO+. A few exam- observation, due to the bright and users may expect release of SV data in ples are shown in Figure 3. numerous lines and plenty of comparison the coming months. data to check against (see Zapata et al. The low-mass multiple protostar and hot [2011] for a recent study). The ALMA SV High angular resolution corino IRAS16293 (Ceccarelli et al., 1998; data surveys the lower two thirds of The longest baselines for Cycle 1 will be Jorgensen et al., 2011) was ob­­served as Band 6, from 214 through 246 GHz, at ~ 1 kilometre compared with ~ 400 metres part of the SV process of demonstrating a spectral resolution of approximately in Cycle 0. It is necessary to verify that very high spectral resolution in a near- 0.7 km/s. In spite of this being one of the coherence is maintained and that the cal- line confusion condition in Band 6 and to best-studied regions of the sky, the ALMA ibration techniques, particularly phase demonstrate high-frequency observa- SV data, even with only the 16 antennas correction, are working properly on these tions at Band 9. A small mosaic was per- available at the time of the observations, longer baselines. Bright compact formed at Band 9 to properly cover the is of such a high quality that five sepa- sources will be used for this purpose. It is

60 The Messenger 150 – December 2012 ǥ ǥ Figure 3. ALMA SV Band 7 data on the pro-  toplanetary disc ǥ ǥ HD 163296. Left: con-  tours of the CO(3-2) inte- grated line emission are ǥ ǥ shown on top of the con-  tinuum image. Right: The NM 5D NM @SH KNBHS same CO(3-2) integrated @SH ǥ ǥ intensity contours are X JL DBKHM DBKHM 

# overplotted on the mean # R

 velocity map for the  ) )  ǥ ǥ  same line. In both plots the ellipse in the bottom left corner shows the ǥ ǥ  angular resolution.

 l¦nǥ lŒnǥ

R R R GLR  R  R  R  R  GLR        R  )1HFGS RBDMRHNM )1HFGS RBDMRHNM ex­pected that ALMA will be in a position move in right ascension, declination and antennas, data have to be taken and to start these observations at the end of radial velocity (Doppler tracking) work reduced in a different way compared to 2012. correctly in all cases, including both the interferometric data. The three those objects that use the built-in ephem- ­datasets, 12-metre array, ACA and total Ephemeris eris, e.g., planets and major moons, and power, then need to be combined One critical goal is also to demonstrate those for which a special ephemeris has together. Band 9 will be particularly chal- that the special steps required to observe to be uploaded, e.g., comets. Dynamical lenging because, in addition to the usual and reduce the data on objects that selection of phase calibrators is also problems of getting good quality data required since the objects move on the at such high frequencies, the single-dish sky during the possible scheduling data requires a special observing tech- period, so this is an additional observa- nique to separate the signals from the two tory mode (normally transparent to the sidebands. NEE users) that an SV project in this area will verify. NM References Spectral modes Ceccarelli, C. et al. 1998, A&A, 338, L43 Cycle 1 capabilities include cases where Espada, D. et al. 2009, ApJ, 695, 116 the different basebands are used with Fortman, S. M. et al. 2012, Journal of Molecular different spectral modes (time/frequency Spectroscopy, in press domain mode; TDM/FDM) or different Galvan-Madrid, R. et al. 2012, A&A, in press (arXiv:1210.1413) resolutions. The end-to-end process is Helfer, T. et al. 2003, ApJS, 145, 259 more complicated than in Cycle 0, involv- Hirota, M. et al. 2012, ApJ, 757, L1 ing changes to the Observing Tool, the Isella, A. et al. 2007, A&A, 469, 213 control of observations and the data Jorgensen, J. K. et al. 2011, A&A, 534, 100 Jorgensen, J. K. et al. 2012, ApJ, 757, L4 reduction. An important additional capa- @T Mannings, V. & Sargent, A. I. 1997, ApJ, 490, 792 bility is the use of spectral averaging, Niederhofer, F. et al. 2012, A&A, in press which will make the data volume much (arXiv:1210.2526) Figure 4. ALMA SV Band 9 690 GHz continuum smaller in many cases, but again intro- Pineda, J. et al. 2012, A&A, 544, L7 Qi, X. et al. 2011, ApJ, 70, 84 image of IRAS 16293-2422. Jorgensen et al. (2012) duces many additional steps in the end- have identified 13 transitions of the simplest sugar, Shukla, H., Yun, M. S. & Scoville, N. Z. 2004, ApJ, glycolaldehyde, a basic building block of biological to-end observing process, which need to 616, 231 molecules, along with many other complex organic be verified. Testi, L. & Zwaan, M. 2011, The Messenger, 145, 17 molecules, toward the two components of this Wagg, J. et al. 2012, ApJ, 752, L30 Zapata, I. et al. 2012, ApJ, 754, L17 binary system. The green box around one of the Imaging extended structure sources in the image measures 270 au on the side; Zhao, J.-H. & Wright, M. C. H. 2011, ApJ, 742, 50 the spatial resolution of the ALMA observations are This is the most critical and complicated 0.2 arcseconds (25 au at the distance of the of the new capabilities for Cycle 1. ALMA ­Ophiuchus cloud). The insert shows spectra toward has to take well-matched data with the Links the continuum peak of the source (“on”), where the Atacama Compact Array (ACA) and the 1 lines typically are seen as redshifted absorption lines ALMA Science Portal SV page: http://wikis.alma.cl/ indicative of infall, and toward a position offset from 12-metre array and then combine these bin/view/ScienceVerification/ScienceVerificationNot this by about 25 au (“off”), where the lines are seen with the correct scaling and weighting iceboard?cover=print 2 in emission. One of the 13 identified glycolaldehyde into a single cube. When single-dish ALMA Science Portal: http://almascience.eso.org/ alma-data/science-verification lines is indicated in red. measurements are made with total power

The Messenger 150 – December 2012 61 Astronomical News ment ann12079. ment hat, is shown celebrating his award. See Announce with Massimo, Chile. and Europe in astronomy of in recognition of his contribution to the development grace, special by nationality Chilean granted recently was Chile, in Representative ESO Tarenghi, Massimo 64. p. on al. et Walsh by report workshop the See Headquarters. ESO of drive the to entry the at taken ESO of Years 50 First The The group photograph for the workshop ESO@50

- Astronomical News

Switzerland Celebrates 30 Years of ESO Membership

Georges Meylan1 federal governing bodies, along with Martin Steinacher2 astronomers from all the Swiss universi- ties and institutions involved in astro­ physics. The event was organised and 1 Laboratoire d’astrophysique, École chaired by G. Meylan from EPFL, who is ­Polytechnique Fédérale de Lausanne also the Chair of the Swiss Commission (EPFL), Switzerland for Astronomy and science delegate for 2 State Secretariat for Education and Switzerland on the ESO Council. The Research (SER), Bern, Switzerland oral presentations were split into two groups, first political, then scientific, but in both cases past achievements and This year Switzerland celebrated the future challenges were described. 30th anniversary of its accession to ESO. The Swiss contributions to ESO The welcome address, by T. Courvoisier, are briefly summarised and a half-day from the University of Geneva, who is symposium to mark this anniversary is also President of the Swiss Academy of reported. Sciences, emphasised the essential ­benefits of Swiss participation in ESO, in the past and the future. L. Woltjer, former This year is rich in astronomical celebra- ESO Director General and “father” of tions: as well as the 50th anniversary, the Very Large Telescope (VLT), followed on 5 October 1962, of Belgium, France, with a presentation on the theme of Germany, the Netherlands, and Sweden Europe and ESO. Then, M. Steinacher, pooling their resources and ambitions from the State Secretariat for Education under the flag of ESO, the 30th anniver- and Research, and also head of the Swiss sary of the membership of Switzerland to delegation to the ESO Council, presented the Universe, which was awarded the ESO, through the completion of the the path of Switzerland into ESO, the 2011 Nobel Prize in Physics. accession process on 1 March 1982, is main highlights of the Swiss participation also being commemorated. and the major phases of the development All three speakers emphasised past of ESO, with the observatories at La Silla, Swiss participation in the instrumenta- During these last five decades, the (cur- Cerro Paranal, Chajnantor, and Cerro tion related to the New Technology Tele- rently 14) Member States of ESO have Armazones as major cornerstones. scope (NTT) and the VLT/VLT Interfer­ advanced European astrophysical activi- ometer (VLTI), and, hopefully, in the future ties to the level of excellence they enjoy Three scientific reviews summarised the to the E-ELT. The complementarity today. The role of ESO as the world activities of Switzerland in three scientific between these ESO facilities and some leader in ground-based astronomy is areas where numerous recent discover- of the NASA/ESA satellites (HST and confirmed by some recent decisions by ies have been achieved. S. Udry, from the JWST) and ESA satellites (CHEOPS, the ESO Council in relation to the con- University of Geneva (UniGE), summa- EUCLID) was also emphasised, allowing struction the European Extremely Large rised the activities related to the search astrophysicists in Switzerland to acquire Telescope (E-ELT). The Swiss member- for extrasolar planets with ESO tele- both ground-based and space-borne ship of ESO has made a strong impact scopes. The excellent synergy between observations, a key component in main- in instrumentation and observational the universities of Geneva, Bern (UniBE) taining Swiss activities at the forefront of astrophysics, covering many fields from and the Eidgenössische Technische astrophysical research. the search for extrasolar planets to the Hochschule Zurich (ETHZ) is the best most distant galaxies. way to maintain and develop the leader- An aperitif allowed everybody to discuss ship established by UniGE during the last further the future of astronomy and astro- In order to acknowledge the manifold 20 years. M. Carollo, from ETHZ, pre- physics in Switzerland through the ESO contributions of the Swiss people to sented the intense research activities in and ESA projects, with some grateful all activities related to astrophysics, the the field of galaxy formation and evolution thoughts for our Swiss predecessors Swiss Commission for Astronomy, a undertaken at ETHZ, UniGE, Univeristät who pushed for direct participation of board of the Swiss Academy of Sciences, Zurich, and EPFL, from the points of view Switzerland in these outstanding interna- organised a small symposium, which of observations and numerical simula- tional organisations. was hosted in the Federal Capital by the tions. B. Leibundgut, Director for Science University of Bern, on the afternoon of at ESO, and inci­dentally the highest 5 October 2012. The general theme was: ranked Swiss staff member at ESO, pre- Acknowledgements Astronomy in Switzerland: The Quest sented the impact of ESO telescopes on We are extremely grateful to Chantal Taçoy (UniGE) for Summits! Nearly 150 participants recent progress in cosmology, e.g., for her very efficient organisation in all aspects of this attended this event, among them numer- through the direct contribution to the dis- meeting. Our thanks also to Mirjam Kaufmann ous members of the Swiss academic and covery of the accelerated expansion of (UniBE) and Claire Schatzmann (EPFL) for their help.

The Messenger 150 – December 2012 63 Astronomical News

Report on the Workshop ESO@50 — The First 50 Years of ESO held at ESO Headquarters, Garching, Germany, 3–7 September 2012

Jeremy Walsh1 Young stars and planets Transients Eric Emsellem1 Michael West1 ESO’s next major milestone, the Atacama Steven Smartt (Belfast) summarised Large Millimeter/submillimeter Array detection and follow-up surveys for bright (ALMA) featured strongly in the first few transients which have recently begun at 1 ESO talks. Some of the first Cycle 0 results La Silla Observatory. The La Silla–QUEST in young stars and star-forming regions survey (see Baltay et al., p. 34) produces were presented by Leonardo Testi (ESO) transient alerts within days and these In recognition of the 50th anniversary where the high spatial resolution and sen- are followed up spectroscopically by the of the signing of the ESO Convention, a sitivity of ALMA will bring many ad­vances. Public ESO Survey of Transient Objects special science workshop was held at The field of astrochemistry was covered (PESSTO) with EFOSC on the New Tech- ESO Headquarters in Garching to focus by Ewine van Dishoeck (Leiden), con­ nology Telescope (NTT). on the main scientific topics where centrating on very high spectral resolution, ESO has made important contributions, including some ALMA spectra from pro- The Very Large Telescope (VLT) was very from Solar System astronomy to funda­ toplanetary discs, demonstrating the well timed for the beginning of the era mental physics, and to provide a per­ potential for finding new species (up to of observations of gamma-ray burst after- spective for future scientific challenges. 50% of lines are unidentified). High-mass glows. The seminal object 1998bw, The workshop is summarised. star formation in clusters was presented a supernova (SN) associated with a weak by Guido Garay (Universidad de Chile) gamma-ray burst and extensively ob­­ who highlighted the contributions of the served by ESO telescopes, began the The five-day workshop ambitiously Swedish ESO Submillimetre Telescope exploration of the now fruitful SN– c­overed a vast range of topics in optical, (SEST) and more recently the ATLASGAL gamma-ray connection, as reported by infrared and millimetre/submillimetre survey with the Large Bolometer Camera Johan Fynbo (Niels Bohr Institute). astronomy on which ESO telescopes (LABOCA) on the Atacama Pathfinder have concentrated over the last 50 years. Experiment (APEX). Topics ranged from the planets and The Milky Way moons of the Solar System, extrasolar Two invited talks were devoted to the planets, stellar evolution, star clusters, Solar System, one on the planets and The major role that ESO facilities have the Galactic Centre, Galactic structure to moons by Bruno Sicardy (IAP) and played in studies of the Milky Way nearby galaxies, dwarf and giant, to one on small bodies by Pierre Vernazza was covered by Marina Rejkuba (ESO), ­quasars and active galactic nuclei to gal- (ESO). Occultations play an important ranging from large surveys with high axy surveys and the distant Universe. As role in determining the structure of Solar ­resolution spectroscopy dating back to well as focussed contributed talks (21) System bodies by exploiting fast read- the 1980s to the current imaging surveys and poster papers (15), there were invited out modes and also adaptive optics with the survey telescopes VISTA (VVV) reviews (25) covering a broader range imaging with NACO. ESO telescopes and the VST (VPHAS+) and the Gaia– and five plenary talks putting ESO astron- have been instrumental in the detection ESO spectroscopic survey. Pavel Kroupa omy in the widest context. As befits the and characterisation of small bodies — (Bonn) covered the evidence for system- celebratory tone, there were many and comets, asteroids and trans-Neptunian atic variations of the stellar initial mass diverse social activities, from a welcome objects (TNOs). function, demonstrating that ESO facili- reception at ESO on the evening of the ties have made many essential contri­ first afternoon of the workshop, an infor- Stephane Udry (Geneva) reported there butions. Giampaolo Piotto (Padova) mal dinner in a Biergarten in Munich, a were 777 extrasolar planet candidates showed how the old paradigm of a glob- more formal workshop dinner in a restau- at the time of the meeting, of which 715 ular cluster as a single population of rant in Garching, “beer and brezen” in had been detected by the radial velocity ­co-eval stars has been overturned in the auditorium on the penultimate even- technique. The large HARPS allocation favour of globular clusters as an assem- ing and a farewell lunch on the Friday (100 nights/year over five years) has been bly of multiple populations showing ­following the last session. A photograph crucial, with a variety of programmes an Na–O (and Mg–Al) anticorrelation. of the participants is shown on p. 62. ­targeting stars of different types (early- FLAMES in its Medusa modes (130 and late-type, giants and dwarfs, young ­simultaneous single-object spectra) has The contributions are available (in PDF) and older stars). Francois Bouchy (IAP) revolutionised the field and enabled on the conference website1. For the followed with a talk on transiting planets; chemical abundances in many clusters to first time at ESO the proceedings were many detected with the CoRoT satellite be measured. Reinhard Genzel (MPE) webcast and the recordings of each have been followed up with ESO tele- described two decades of high precision presentation are also available on the scopes and instruments. infrared imaging and astrometry on the website. We present a brief summary of Galactic Centre. One of the highlights the topics covered in the plenary and was the observation of a complete orbit invited talks. for the star S2 from 1992–2012 as it ­travels around the central black hole,

64 The Messenger 150 – December 2012 encompassing many NTT and VLT astro- spectroscopy (IFS) with SINFONI at the of quasars using the many-multiplet metric measurements. VLT with adaptive optics has enabled method, the two datasets show evidence the kinematics and structure at 1–2 kpc for a dipole in the sky distribution of Δα/α scales of the star-forming regions to be at 4.1σ level. Nearby galaxies studied. Many more targets will become accessible with KMOS, currently being Dwarf galaxies of the Milky Way and the commissioned on the VLT and in the Instrumentation Local Group were discussed by Eline longer term by E-ELT IFS instruments. ­Tolstoy (Groningen). GIRAFFE and UVES Guy Monnet (CRAL) presented a his­ have provided important data on the Yannick Mellier (IAP) provided an over- torical outline of ESO’s contributions and chemical evolution timescales for these view of gravitational lensing studies, innovations in instrumentation. Sandro galaxies and detailed spectroscopy ­noting that the first quadruple gravitation- D’Odorico (ESO) then went through the of more distant dwarf galaxies will be ally lensed galaxy was detected by the development of instrumentation at ESO, achievable with the European Extremely MPG/ESO 2.2-metre telescope in 1988 following his close involvement from 1981 Large Telescope (E-ELT). The Magellanic and the redshift determination of the to his emeritus appointment in 2010. Clouds have naturally proved a rich large arc in the galaxy cluster A370 with The instrumentation plan for the VLT was ­pasture for ESO telescopes and they the 3.6-metre. From 1990–1997 ESO defined with the community at an early have explored many of the objects that supported the EROS microlensing survey stage and for the E-ELT the paradigm act as astrophysical probes in these, with the 1.0-metre MarLy telescope at was significantly extended, with ESO the nearest, and lower metallicity galax- La Silla and from 2002–2012 the PLANET coordinating 11 studies for instruments ies, as shown by Carme Gallart (IAC). consortium using the Danish 1.54-metre. and adaptive optics modules, of which Marijn Franx (Leiden) treated ESO’s role two concepts were accepted as first-light Francoise Combes (Observatoire de Paris) in the study of galaxy evolution at high instruments (a diffraction-limited near- discussed observational approaches redshift, highlighting the early influential infrared imager and a single-field near- to understanding the triggering and regu- surveys COMBO-17, a 17-filter imaging infrared wide-band integral-field spectro- larisation of star formation in galaxies. programme with the MPG/ESO 2.2-metre graph).

Although H2 is key for star formation it is telescope and the wide-field imager very difficult to observe directly, so CO (WFI), and the K20 survey of extremely is the favoured tracer. ALMA is set to red objects with FORS on the VLT. Plenary talks bring CO and other molecular tracers in normal galaxies at high redshift within the Alvio Renzini (Padova) presented a per- realm of study. Cosmology sonal view on ESO’s important influence on astronomy in Europe, noting that The talk by Mark Sullivan (Oxford) on approval of the VLT was seen as a turning Distant galaxies and clusters supernova cosmology began with an point from small to big science. Large ­historical overview of the first ESO sur- Guaranteed Time Observing (GTO) alloca- The great impact of the VLT on large- veys of SN Type i a as cosmological dis- tions to instrument consortia, Large scale redshift surveys was summarised tance probes, dating from the late 1980s. ­Programmes and most recently Public by Simon Lily (ETH Zurich) who noted More recently VLT observations have Surveys, have led to progress on major that of the ~ 100 000 spectroscopic red- contributed to refining the value of the problems and areas of astrophysics. shifts to z > ~ 1 about two thirds are cosmological equation of state parame- These large programmes typically pro- from the VLT. We are currently in a golden ter, w, whose value seems to be very duce a larger impact per night, in terms age for the exploration of the distant close to –1 (­Einstein’s cosmological con- of papers and citations, compared to ­Universe. Linda Tacconi (MPE) showed stant). Absorption lines arising in the dif- small programmes. how ESO is perfectly tuned to answer fuse intergalactic medium and dense many of the big questions in cosmic star interstellar medium along the line of sight Massimo Tarenghi (ESO) gave an enthu­ formation history and ALMA will open to ­quasars were considered by Patrick siastic talk on the history of the ESO up the field of mapping the rotation Petitjean (IAP). The spectrum of the first observatories from the 3.6-metre to the curves of disc galaxies at z ~ 1. Active quasar was obtained in 1962, but it was NTT (for which he was Project Manager) galactic nuclei (AGN) have been known not until the commissioning of UVES on at La Silla, to the VLT (where Massimo from around the time of the signing of the VLT in 1998 that extensive surveys was the first Director) and onwards to the ESO convention and, as Carlos de of quasar absorption lines took off at ALMA (where he also served as Director). Breuck (ESO) showed, their increased ESO. Michael Murphy (Swinburne) con- numbers and luminosities at higher sidered the astronomical evidence that Richard Ellis (Caltech) presented a talk on z made them ideal targets with which to the fundamental constants (in particular the global impact of ESO. In its formative investigate galaxies. Natascha Förster- the fine structure constantα ) are varying years (1962–1986) ESO showed a strong Schreiber (MPE) described spatially throughout the Universe. Based on high- diversity of high performance instrumen- resolved studies of the kinematics and resolution spectra with UVES (153 absorb- tation including the infrared, pioneered structure of early galaxies. Integral field ers) and HIRES on Keck (142 absorbers) by the late Alan Moorwood. The NTT era

The Messenger 150 – December 2012 65 Astronomical News Walsh J. et al., Report on the workshop “ESO@50 — The First 50 Years of ESO”

(1986–1996) was based not only on the success of this innovative new telescope, but also planning of the VLT and expan- sion of instrumentation at La Silla includ- ing the SEST, which initiated ESO’s route into the submillimetre. For the VLT era (1998–present), he compared some of the science cases in 1997 with those achieved with the VLT and demonstrated that new telescopes achieve far more than their original science cases. He closed by looking forward to the Extremely Large Telescope era with the Giant Magellan Telescope (GMT), the Thirty Meter Telescope (TMT) and the E-ELT.

Bruno Leibundgut (ESO) examined the synergies between ground- and space- based observatories. Examples of the ­relative advantages of ground versus space measurements were made and the example of SN1987A was used to show how a multi-wavelength approach is Figure 1. The Director General, Tim de Zeeuw, out- likely the exoplanet field will continue to essential to arrive at a fuller picture of the lining future perspectives for ESO at the conference. be a high priority one. Technology devel- many features of the evolving supernova opments should be harnessed to improve remnant. The presence of the Space and extend the capability of instruments. ­Telescope European Co-ordinating Facil- in 2013 with the aim to finalise the white This assumes, of course, that society ity, which was hosted by ESO from 1984 paper by end of 2013. continues to be interested in scientific to 2010, provided many synergistic bene- advancement; outreach has a role to play fits with Hubble Space Telescope prac- here. ESO operates within a world astro- tice and operations, such as operations Closing remarks nomical community and a degree of models and the science archive. In addi- competition in the optical/infrared­ field is tion, the link with the European Space Tim de Zeeuw summarised ESO’s mis- healthy for future progress. Agency improved coordination of ground sion and accomplishments during the and space missions, such as ground- past half century in developing and oper- Strategically some moderate further based support for the Rosetta and Gaia ating world-class observing facilities growth by the addition of new ESO missions. for astronomical research and organising ­Member States was advocated, and will collaborations (see Figure 1). He then bring added value without leading to Roberto Gilmozzi presented a white provided a perspective for the next 10–15 over-dominance (ESO currently involves paper, for discussion, on Paranal in the years: about 30% of the world astronomical era of the E-ELT, seeking community – keep Paranal as a leading observatory community). ESO’s successful opera- input to the two questions: with an integrated system of VLT, VLTI, tional model should be retained with a – Is the VLT operations model suitable for VST and VISTA; mix of multi-purpose telescopes and the E-ELT? – maintain and upgrade instruments and experiments, in combination with strong – What is the future of the VLT in the next replace them with second generation national programmes and strong con­ decade 2020–2030? instruments; nections between the Observatory and He sketched the facilities considered – add the E-ELT into this system; the astronomers in the Member States to be available circa 2025, the instru- – further develop ALMA; (through community involvement and a ments still operating on the VLT and what – continue the fruitful partnership with mix of visitor/service observing modes). the extant scientific questions might be. the community such as, for example, Around the end of the decade a new tele- A range of tactical and strategic options hosting experiments on La Silla, build- scope project could be perhaps contem- were presented. The initial ideas have ing instruments and providing student- plated in close connection with space been presented to the ESO committees — ships and fellowships. observatories and other ground-based the Scientific Technical Committee (STC) astronomy developments. and Council — and internally to ESO The Director General tried to envision astronomers. The aim is to incorporate astronomy 50 years from now, emphasis- feedback in a white paper to be subse- ing that surely new questions will arise Links quently iterated in the next six months, and paradigm shifts will occur in the way 1 ESO@50 workshop programme: http://www.eso.org/ leading to a community-wide workshop astronomy is done in the future, but most sci/meetings/2012/ESOat50/program.html

66 The Messenger 150 – December 2012 Astronomical News

Report on the Workshop Science from the Next Generation Imaging and Spectroscopic Surveys held at ESO Headquarters, Garching, Germany, 15–18 October 2012

Marina Rejkuba1 Magda Arnaboldi1

1 ESO

Over 100 participants gathered to pre­ sent and discuss the first exciting results from the eleven ESO public sur­ vey programmes in the context of cur­ rent and planned major ground- and space-based surveys. The VISTA and VST public surveys presented a wide range of new scientific results. Presen­ tations of other current or planned large ground- and space-based projects pro­ vided a benchmark for the ESO public surveys and their relevance worldwide.

Introduction Figure 1. The conference photograph on the stairs of ESO and European astronomy have firmly the entrance hall of ESO Headquarters. entered the era of large public surveys with the addition of the VLT Infrared Sur- data mining challenges. The presenta- by 2028. Mellier emphasised the need vey Telescope (VISTA) and the VLT Sur- tions are available from the conference for complementary ground-based photo- vey Telescope (VST) to the Paranal tele- web page1. metric and spectroscopic observations scope suite and the start of the first for the ultimate goal of the mission: spectroscopic public surveys. The official The ESO Director General, Tim de Zeeuw, understanding the Universe’s accelerat- start of VISTA operations was in April opened the workshop, outlining the key ing expansion by deriving the properties 2010, and the six VISTA imaging public role that surveys play in astronomical and nature of the dark energy and test- surveys have collected over 2.5 years research. They provide an inventory of ing the law of gravity on large scales. worth of data; the opening day of the the Universe, allowing astronomers to find workshop coincided with the first anni- rare objects, and, on account of large A. Connolly presented the scientific versary of VST operations. Since January number statistics, allow measurements of potential of the Large Synoptic Survey 2012, two public spectroscopic surveys key parameters in cosmology. The scale Telescope (LSST) and its scientific driv- have been collecting data, at the VLT of current surveys changes the way ers: dark matter, dark energy, cosmology, Unit Telescope (UT2) and the New Tech- astronomical research is done by sup- time-domain astrophysics, structure nology Telescope (NTT). The main aims porting the formation of very large teams of the Solar System and Milky Way struc- of the workshop were the presentation and by providing the astronomical com- ture. These drivers motivate a uniform of the goals of the ESO public surveys munity with public data at a high level of cadence for multi-epoch observations and their first scientific results. The global processing, for further scientific analysis. and 90% of the southern hemisphere context of ESO surveys was provided accessible from Cerro Tololo observatory by presentations of other current and Survey facilities from ground and space will be covered every 3–4 nights. The planned large ground- and space-based were the topic of the first session. M. final survey will accumulate, over ten surveys. Capaccioli, the Principal Investigator (PI) years, 1000 visits in ugrizy-bands to reach of VST, and J. Emerson, the PI of VISTA, r ~ 27.5 mag (36 nJy) and ~100 Pbytes ESO public survey science covers a wide described the two latest imaging survey of data. This unique facility is in its design range of topics. In only three and a half facilities on Paranal, presenting their and development phase, with expected days, more than 50 talks showed exciting characteristics and capabilities, together commissioning in late 2020. new results in the fields of star formation with a short summary of the ESO public and the structure of our own Galaxy, the imaging surveys (see also Arnaboldi et The year 2013 will be a decisive one nearby Universe and all the way out to al., 2007). The European Space Agency for the next generation of large spectro- high-redshift studies with both very deep Euclid project was presented by Y. scopic survey instruments at ESO. M. and wide surveys. In addition to the oral ­Mellier: this imaging and spectroscopic Cirasuolo and R. de Jong presented contributions, 20 poster presentations facility, to be launched in 2020, will the two competing projects: MOONS covered similar topics, and provided carry out a survey for 5.5 years, and pro- and 4MOST (Multi-Object Optical and details on survey facility operations and duce about 10 Pbyte of processed data Near-infrared Spectrograph and 4-metre

The Messenger 150 – December 2012 67 Astronomical News Rejkuba M., Arnaboldi M., Next Generation Imaging and Spectroscopic Surveys

Multi-Object Spectroscopic Telescope; with ~ 2000 VST/OmegaCAM fields models of galaxy formation since its see also Ramsay et al., 2011). These two observed in ugri and Hα filters. This sur- results show that it is difficult to make the spectrographs are quite complementary, vey will provide a 3D extinction map and whole Milky Way halo out of low luminos- the former being designed for the VLT the census of the Galactic Disc, ena- ity dwarf spheroidals. and working in the near-infrared (NIR) with bling detailed study of star clusters and 1000 fibres (Cirasuolo et al., 2011), while star-forming regions in the Galaxy. the latter expects to go to VISTA and High-z Universe, galaxy evolution and work primarily in the optical with 2400 The latest addition to the ESO public cosmology fibres (de Jong, 2011). Their science ­surveys exploring the Galaxy is the cases include Galactic archaeology, gal- Gaia–ESO spectroscopic survey led by The high-redshift Universe session axy evolution and cosmology, and have G. Gilmore and S. Randich. This survey started with the Ultra-VISTA survey strong synergies with the ongoing imag- addresses key open issues in the forma- re­sults presented by H. J. McCracken. ing public surveys. tion and evolution of the Milky Way and The wide part of the survey covers its stellar components based on accurate 1.5 square degrees in the Cosmic Evolu- The core of the workshop programme radial velocities and abundances from tion Survey (COSMOS) field, and is now consisted of invited talks by the 11 ESO VLT FLAMES spectra, to complement completed. The deep and the narrow- public survey PIs. The VISTA Deep Extra- Gaia observations in the coming years. band (using the NB118 filter) survey com- galactic Observations (VIDEO) PI, M. The science drivers require uniform ponents are still ongoing. The narrow- Jarvis, described the 12-square-degree ­analysis, resulting in yearly advanced band part of this survey is designed to survey covering the XMM-Newton Large- data releases as described by Randich. findz ~ 7 Lyman-break galaxies and Scale Structure (XMMLSS), Chandra The Gaia–ESO survey started in January z = 8.8 Lyman-alpha emitters, and has Deep Field-South (CDFS) and European 2012, but the nearly completed RAVE already identified four robust sources Large-Area Infrared Space Observatory (Radial Velocity Experiment) survey, pre- with mean redshift 6.98 ± 0.05. At the (ELAIS-S1) fields, with the aim of tracing sented by M. Steinmetz, has already same time the deep NIR Ultra-VISTA the formation and evolution of galaxies ­collected more than 500 000 stellar spec- data has uncovered the real nature of over a large range of redshifts, and over a tra. These are analysed for kinematical several other luminous sources that were survey area large enough that the impact tomography of the Galactic Discs originally claimed to be at z > 7, but of environmental effects can be studied. and study of the presence of substruc- turned out to be at much lower redshifts ture and tidal debris, and large-scale (“only” z = 2–4) instead. Another source deviations from axial symmetry. of contaminants for these high-redshift The Milky Way galaxy and local Universe objects are T-dwarf stars — a treasure The Local Universe session started with trove for low-mass star formation studies. The second session began with an an invited talk on the VISTA Magellanic ­overview of the VISTA and VST imaging Cloud (VMC) survey by M.-R. Cioni. The The VISTA Hemisphere Survey (VHS) ­surveys of the Milky Way. D. Minniti pre- Y, J and Ks filters are used to obtain a and the VST ATLAS survey were pre- sented the status and the first results deep picture of the Large and the Small sented by their PIs, R. McMahon and T. from the VISTA Variables in the Via Lactea Magellanic Clouds as well as of the Shanks respectively. These are wide-area (VVV) Survey. His talk was followed by Bridge and Stream regions. This survey surveys that will enable studies of rare several contributions describing the is unique because of its depth and sources at all redshifts, from nearby search for RR Lyrae stars (by I. Dekany) ­multi-epoch data (12 epochs) that are L-dwarfs to highly obscured broad line and the search for the young star clusters used to determine the 3D structure of the quasars at z = 2, as well as very rare (by J. Borissova) in the VVV area. R. Saito Magellanic Clouds with Cepheids and ­luminous quasars up to z ~ 7. These two ­presented the 84-million-star colour–­ RR Lyrae variable stars. Following on, L. surveys will be used to determine the magnitude diagram of the Galactic Bulge: Girardi presented the main driver of the dark energy equation of state by detect- this large dataset can now be analysed­ survey: the determination of the spatially ing “baryon wiggles” in the power spec- in the same way as an external galaxy! resolved star formation history of the trum of about half a million galaxies. The large-scale extinction and metallicity Magellanic Clouds. maps for the Milky Way were presented The Kilo-Degree (KIDS) and VISTA Kilo- by M. Rejkuba. G. Battaglia summarised the main results degree Infrared Galaxy (VIKING) surveys, from the Dwarf galaxies Abundances & presented by PIs K. Kuijken and W. The PI of the optical Galactic survey Radial velocities Team (DART) VLT/ Sutherland, respectively, constitute VPHAS+, J. Drew, described how it will FLAMES spectroscopic survey of dwarf another pair of complementary VST and be combined with the northern hemi- spheroidal galaxies. She concluded VISTA public surveys. The combination sphere Galaxy surveys IPAS and UVEX that it is necessary to look at many stars of optical and NIR photometry enables a surveys to contribute to European Galac- in order to derive velocity and metallicity clear separation of galaxies from stars, tic Plane Surveys. The northern hemi- gradients as well as to explore the sig­ hence creating highly complete galaxy sphere surveys started in 2003, and now nificance of the multiple kinematic com- samples that are useful for weak lensing VPHAS+ is filling up the 1800 square ponents in these small galaxies. This studies. Since the image quality of the degrees of the southern Galactic Plane ­survey has implications for the current VST is about a factor two better than the

68 The Messenger 150 – December 2012 Astronomical News

Sloan Digital Sky Survey (SDSS), these Pipelines, data mining and survey data ucts from ESO public surveys and large surveys provide a detailed picture of the products programmes (see also Arnaboldi et al., structure of galactic halos as function 2011), and a live demo by J. Retzlaff of galaxy type and environment. KIDS The last session of the workshop was of the new ESO catalogue query inter- and VIKING have already uncovered qua- dedicated to pipelines, data products face, now deployed in the ESO Science sars at z > 6.5, with three candidates and data mining. The KIDS team with Archive Facility. spectroscopically confirmed (talk by B. Astro-WISE has an integrated data han- Venemans). dling system presented by G. Verdoes- Kleijn, while R. Smareglia presented the References S. Smartt presented PESSTO, the data handling and archiving system of Arnaboldi, M. et al. 2007, The Messenger, 127, 28 spectroscopic­ public survey aimed at PESSTO. The six ESO public surveys with Arnaboldi, M. et al. 2011, The Messenger, 144, 17 exploring the physics of supernova VISTA rely on the data processing car- Cirasuolo, M. et al. 2011, The Messenger, 145, 11 ­explosions and a detailed study of tran- ried out in the UK centres, Cambridge de Jong, R. 2011, The Messenger, 145, 14 sients, unusual, and currently unknown, Astronomical Survey Unit (CASU) and the Ramsay, S., Hammersley, P. & Pasquini, L. 2011, The Messenger, 145, 10 types of variable sources. The targets Wide Field Astronomy Unit (WFAU) in for this ­survey come primarily from the Edinburgh, and the latter was presented La Silla–QUEST variability survey by N. Cross. The workshop closed with Links described by C. Baltay (see the article the presentation of M. Romaniello on the 1 Conference web page: http://www.eso.org/sci/ on p. 34). ESO Phase 3 process for the reception, meetings/2012/surveys2012.html validation and publication of data prod-

Retirement of Preben Grosbøl

Dietrich Baade1 Figure 1. Preben ­Grosbøl at his retire- ment party at ESO Headquarters receiving 1 ESO a framed photograph from the Director ­General Tim de Zeeuw. On 31 October, exactly half a year after Klaus Banse’s retirement (Ballester & Péron, 2012), Preben Grosbøl, the other father of ESO’s former MIDAS image ­processing system, retired, marking the end of an era. Preben’s contributions to develop and promote MIDAS, ranging from specialised numerical algorithms to fundamental over-arching concepts, were central to the success of MIDAS (and its predecessor IHAP). However, his lifetime achievements go far beyond that. The third of a century of his affiliation with ESO was devoted to the support of many other initiatives to serve optimally the Copenhagen in 1977. For his thesis, he dy­­namics, star formation and evolution. community’s needs for efficient, reliable worked closely with George Contopoulos He combined careful optical and infrared and versatile data reduction capabilities. in Thessaloniki, Greece, where he also ob­servations with detailed theoretical met his wife Barbara. Throughout his model calculations; the results have Preben was born in Denmark and ob­­ ­scientific career, Preben studied the materialised in several dozen refereed tained his PhD from the University of prop­erties of spiral galaxies: structure, publications. After his retirement, Preben

The Messenger 150 – December 2012 69 Astronomical News

plans to further focus on unravelling the in supporting users of complex ground- but by serving as a catalyst and focus of spiral and central bar pattern of the Milky based observing facilities. community-based efforts. Among other Way, thereby continuing the scientific initiatives, this was achieved through a restlessness that already drove him well As a highlight, he was one of the recipi- series of well-attended ESO/ST-ECF Data before enrolling at university. ents of the 21st Century Achievement Analysis Workshops and the infrastructure Award from the Computerworld Honors enabling VLT/I instrument consortia to Preben was one of ESO’s first postdoc- Program presented to ESO (2005). deliver software modules suitable for inte- toral fellows and for one year (1979/1980) ­Preben also showed remarkable judg- gration with ESO’s data flow system, was still based in Geneva, where ESO ment in anticipating major technological which ultimately aims at the delivery of was hosted by CERN. He has been Head developments in the IT markets: data- ­science-ready data products. of the Image Processing Group, the Sci- base systems, operating systems and ence Data Analysis Group, and the Data hardware for astronomical data process- A farewell party was held at ESO Head- Pipeline Group. For several years, he was ing. His pioneering efforts to introduce quarters on 30 October 2012, where, on Deputy Head of the Data Management new working concepts such as configu- the one hand, many people expressed Division, and eventually even moved to ration control, object-oriented program- their regret at Preben’s departure but, on submillimetre wavelengths and the ALMA ming, software modelling tools, etc. fur- the other, convinced themselves that he Division in Garching. He chaired the ther consolidated the results. Although is leaving full of energy for new undertak- OPTICON Network 3.6 on Future Astro- Preben’s knowledge in these matters was ings, not just scientific and technical nomical Software Environments and the hardly rivalled, he always approached ones. Many words of warm personal and IAU FITS Working Group. Preben was a new themes in a team-based fashion and professional appreciation accompany member of numerous ESO internal work- in an open and cooperative spirit. This Preben Grosbøl. ing groups, often as chair, always as one combination earned him the deep re­­spect of the most active and knowledgeable of everyone working with him and made players: the Computer Coordination him an effective leader. References Group, VLT User Software Advisory Ballester, P. & Péron, M. 2012, The Messenger, Group, VLT Data Flow System Working As in the instrumentation area (D’Odorico 148, 52 Group, Data Interface Control Board et al., 1991), Preben was one of the first 2005, The Messenger, 120, 52 to name just a few that have laid the foun- to realise that ESO would maximise its effi- D’Odorico, S., Beckers, J. & Moorwood, A. 1991, dation for ESO’s leading position today ciency not by doing everything in-house The Messenger, 65, 10

Announcement of the ESO Public Survey Catalogue for Ultra-VISTA available from the Science Archive Facility

The Ultra-VISTA1 survey, targeting a sub- with narrow-band NB118 observations from which the data are extracted on area of the COSMOS field, represents the covering the “ultra-deep stripes” area. request, according to the constraints and deepest of the six near-infrared ESO pub- output format specified by the user. lic imaging surveys, which are currently The catalogue was prepared by the Ultra- being executed at the Visible and Infrared VISTA team for the first catalogue release Additional Phase 3 catalogue data, which Survey Telescope for Astronomy (VISTA). (DR1) and delivered through the ESO are being submitted by VISTA public The first release of the new infrared source Phase 3 system2 for publication to the ­survey teams, will soon be made available catalogue in the COSMOS field is now ESO community. It is now accessible from through the ESO Catalogue Facility. accessible from the ESO Science Archive the Science Archive Facility through a new Facility through a new powerful user inter- dedicated user interface with powerful face for querying and data download. search options and download capabili- Links ties3. The ESO Catalogue Facility comple- 1 Ultra-VISTA survey homepage: The Ultra-VISTA Ks-selected [5σ limit ments the existing functionality by adding http://www.ultravista.org/ Ks = 23.7 AB mag] matched source cata- the possibility to query catalogues by con- 2 ESO Phase 3 data releases: http://www.eso.org/ logue contains 331 077 sources observed tent using positional and non-positional sci/observing/phase3/data_releases.html 3 in Y-, J-, H- and Ks-bands over the full constraints. To this end the catalogue data ESO catalogue facility query interface: http://www.eso.org/qi “deep” survey area of 1.8 square degrees, is stored in a dedicated data-base system

70 The Messenger 150 – December 2012 Astronomical News

Staff at ESO

Peter Gray

Returning to ESO after an absence of eleven years feels very much like coming home. The ESO I knew from those heady days of the VLT construction and the birth of the Paranal Observatory still feels very much the same. There are many familiar faces from those days, my Garching col- leagues and the many co-workers with whom I shared the excitement of building the VLT and setting up Paranal Engineer- ing. Equally as enjoyable is the chance to meet so many new faces, many young people along with experienced older new-hands. ESO has certainly grown, both in numbers of people, but also in the depth and breadth of the experience and expertise of its staff, but it retains the Peter Gray same look and feel of ESO as “the” place of technical and scientific excellence in my trade, I launched my career as an processes were gradually built up into the astronomy, telescopes and instrumenta- astronomical engineer and spent the successful engineering support team at tion engineering. After nearly thirty years next twenty years moving around interna- Paranal, which has continued to the pre- of working in engineering at many of the tionally among most of the major obser- sent day. world’s major observatories, it really does vatories in the world, working in instru- feel like coming home. mentation, engineering operations At the end of 2001, after five years of the support and large telescope projects. most exciting time of my life at Paranal, How I ended up working as an engineer I was on the look-out for new challenges. in astronomy is an interesting story. I When I first left Australia in 1992, I I decided to switch wavelengths and try started out at the University of Sydney in worked for five years at Steward Obser- my hand at radio astronomy engineering Australia studying physics, then mechani- vatory in Tucson, Arizona on a variety so I left Paranal to take up a position cal engineering. As part of the engineer- of projects including mirror casting and with the National Radio Astronomy Ob­­ ing degree it was necessary to spend polishing in the Mirror Lab, the Multi-­ servatory (NRAO) in the US ALMA project time working in industry. My first choice Mirror Telescope (MMT) telescope 6.5- office in Charlottesville, Virginia. During at the time was working for a large hydro- metre upgrade, the Large Binocular Tele- this time I worked closely with many of electricity company, since it sounded fun scope and various other instrumentation the ALMA project staff, both at NRAO to travel around to remote places, looking projects. That was an exciting time, and ESO, and became familiar with the after dams and pumps. However as fate ­working for Roger Angel and other people techniques, technologies and instrumen- would have it, I didn’t get the job and was at the Mirror Lab, audaciously casting tation of millimetre-wave astronomy. I forced to take my second choice, work- and polishing big mirrors in the base- left the ALMA project at the end of 2002 ing at the Anglo–Australian Observatory ment of the University of Arizona football and moved on to the Gemini Observatory (AAO) in Sydney and some exciting stadium. as Associate Director of Engineering. months up at the 4-metre Anglo Australian Telescope at Coonabarabran. Those In 1997 I started work for ESO in Chile For the next five years I worked as the were the days when 4-metre telescopes as the Assembly, Integration and Verifica- Head of Engineering at Gemini Observa- were state of the art, when program- tion (AIV) manager for the VLT project. I tory where I built up the operational engi- ming meant punched cards and everyone was responsible for the organisation, neering support to transition the Gemini was happy to have 3-arcsecond images. coordination and execution of the AIV telescopes from commissioning to rou- work up until first light of the four VLT tel- tine science operations and used my I ended up liking it so much that after escopes. This work began with the first ­Paranal experience to implement a similar graduation I started working at the AAO telescope in 1997 when Paranal existed set of engineering operations systems as a young mechanical engineer, helping as a construction site. As each VLT was and procedures. During this time I led the build instruments and improving tele- finished, we continued to provide engi- Gemini engineering team through a num- scope performance. During this time I neering support to Commissioning, and ber of advanced developments includ- helped pioneer the technique of multi- then Science, Operations. As Paranal ing low emissivity silver coatings and object spectroscopy using optical fibres, transitioned from construction to opera- laser guide star adaptive optics systems. which has now been extensively exploited tions, my position became one of Head by the AAO and other major observato- of the Engineering Department. The During the last four years I have worked ries. After ten years at the AAO, learning ­infrastructure, staffing and engineering as the Assistant Project Manager at the

The Messenger 150 – December 2012 71 Astronomical News

Thirty Meter Telescope (TMT) Project last 20–30 years of my working life in big cycling is my current passion, which is Office in Pasadena, California. I worked projects and astronomical organisations how I met my wife, Leslie. Although on a number of tasks, including the to help ESO deliver the largest and most ­Californian, Leslie has actually spent design and planning of the telescope technologically advanced telescope so far. most of her life in northern Montana as enclosure and structure, project assis- a cowgirl, backcountry horse riding, tance to the TMT–Japan project offices, In between times, those who know me, ­skiing, hiking and road cycling. Leslie and the investigation and planning of the know that I’m seldom idle outside of work I now have a combined “stable” of twelve on-site construction phase and the on weekends. bicycles, including several beloved detailed long-term operations planning ­Pinarellos. As well as sharing her passion for the observatory. Over the years, whatever the remote for road bikes, Leslie shares with me location of the observatory, I’m always our grown-up son Hunter, a young entre- Now back at ESO once again as the Pro- out and about, whether it be paragliding preneur living back in Pasadena, whom ject Engineer for the European Extremely in Tucson, mountain biking at Paranal, we proudly boast is a successful small- Large Telescope (E-ELT) project, I’m using windsurfing in Antofagasta, or kiteboard- business owner employing several people these accumulated experiences of the ing in La Serena and Hawaii. Road and helping to kick start the US economy.

Fellows at ESO

Noé Kains my undergraduate physics degree, I was lucky enough to be supported by schol- Looking back, my path to becoming an arships that enabled me to continue astronomer is perhaps a slightly uncon- my musical education in parallel; some- ventional one. Like most other astrono- thing that would have been very difficult mers, I have early memories of being in Belgium. After working on an astron- interested in space and rockets. I also omy project for my Master’s thesis, I remember being entranced by the night decided to apply for a PhD in astrophys- sky during summer family holidays — ics, which I started at the University of I was lucky to spend entire summers sail- St Andrews in Scotland in 2006. Again, ing around the North Sea, and I particu- throughout my PhD I kept up a busy larly enjoyed sailing at night, which gave musical parallel life, which I think made me plenty of opportunities to get away the PhD experience much easier. I was from light pollution and see the night sky lucky to have a supervisor who fully sup- in all its glory. ported this, even when I disappeared for weeks at a time on concert tours! I was born and raised in Brussels, and During almost four years in Scotland, my moved to London when I was 17 to love for astronomy developed further begin an undergraduate degree in phys- and the fun I had working on my PhD ics at Imperial College, because I enjoyed convinced me that this was the career I physics and maths at school, but also wanted to pursue. because I had decided very early on that Noé Kains I wanted to go and see other things My first observing trip, in 2007, was a than the small country in which I grew up. 23-night run on the 1.54-metre Danish of the Chilean night sky, running outside Apart from my long-standing obsession telescope at La Silla. If 23 long winter between two exposures of the Galactic with London, there was another reason nights did not dent my fascination for Bulge to look at the bright trail of the that I wanted to move to the UK in particu- observing, clearly my commitment to this Milky Way and the Magellanic Clouds. lar. Since the age of six, I had been study­­ was no fluke! Every day I was amazed Two (thankfully slightly shorter) further ing the piano and I knew that the more to wake up in this strange place in the observing runs in La Silla only strength- flexible education system in the UK would middle of nowhere, and every night I ened my attachment to the place, so ESO allow me to pursue both interests. During spent hours marvelling at the splendour was a natural place for me to consider

72 The Messenger 150 – December 2012 when it came to looking for my first post- doctoral position.

Working at ESO is such a privilege — to be surrounded by the people who run the world’s most important observatory, par- ticularly seeing the engineering and politi- cal sides of it, which is something that most scientists easily forget. The sheer number of talks, seminars and colloquia is a testament to this. Most as­tronomers come through ESO at some point or another, which means that, being here, we get to hear and meet many of today’s brightest astronomers. During my Fel­ lowship I have continued my work on Roberto Galván-Madrid exoplanet hunting using gravitational microlensing, and have started new col- laborations, leading me to apply my work Roberto Galván-Madrid philosophy — good decision! — I started to areas of astronomy that I would not my masters in astronomy at the Center necessarily have considered before. Looking at it in retrospect, I don’t know for Radioastronomy and Astrophysics of There is definitely a sense of being lucky how I got here, but I’m very happy that the National University of Mexico (UNAM). to be here at ESO and wanting to make it came to be. I was born in the southeast There I learned a lot from my advisor the most of it amongst the community of of Mexico, in the “small” city (with about Luis F. Rodríguez and several other staff young researchers. Of course, being a hundred thousand inhabitants) of members. In 2007, I was lucky enough an astronomer is a privilege in general: ­Chetumal, in the Yucatan Peninsula. Peo- to be admitted to the predoctoral pro- we are essentially employed to think, and ple there just do not become scientists. gramme of the Smithsonian Institution, get to visit many of the world’s most The natural path within my extended fam- and moved to the Center for Astrophysics incredible places for observing trips, con- ily would have been to become a mer- in Cambridge, Massachussetts, to con- ferences or collaborations. Another ad­­ chant, a bureaucrat, or a politician. Luck- duct my doctoral research working with vantage of being here is that ESO is in ily, my parents always motivated my the Submillimeter Array (SMA) group. the news a lot. It may seem trivial, but it brothers and me to educate ourselves, Those years in “the geekiest town on is a nice feeling when your family and perhaps because they didn’t have the Earth”, with all their ups and downs, have friends have a vague idea of what you do chance to finish professional degrees, a very special place in my memory. as an astronomer, thanks to the amount and there were many lectures at home on Toward the end of my thesis, I also spent of media exposure ESO receives as a which to spend some afternoons after a dreamy season in Taipei, Taiwan, eating world-leading observatory. school. I remember my excitement when I yummy Chinese food. was a kid and discovered some books On the music side — well, of course I that explained things about particle phys- In September 2011 I moved to Munich don’t spend as much time practicing the ics, space travel or the Solar System. and started my ESO Fellowship. I wanted piano or performing as I once did, but the to learn about the European way of doing first “piece of furniture” I bought when I When I finished high school in 2000 I con- things and gain expertise with ALMA, moved to Munich was a piano — before vinced my parents that “I had to leave” and what better place than at the flagship even buying a bed! I still find that the my home town to study physics. Then I astronomical institution on this continent. ­balance in my life between music and my moved to Monterrey to start my college So far I am loving both the scientific “job” is essential. When struggling with degree, a completely different, acceler- opportunities and life in Germany, includ- a science problem I can come home, ated, heavily industrialised city of four ing beer fests and trying to learn to pile practice for a few hours and “reorganise” ­million people in the north of Mexico. I up words as locals do. I envision myself my brain. It really works! remember those years as a period of dis- in the future going back to Mexico and covery where I dived into so much knowl- helping a little bit to the development of After two great years at ESO, it’s unfortu- edge, made some of my best friends in my country — but one never knows! — nately already time to start looking for life, and realised that making contribu- while at the same time strengthening ties my next job. Wherever I go, I know that tions to science was within reach. Five with all the great institutions in which I the experience and contacts I am gaining years later, after discarding the idea of have worked all over the world. Owning here will be a major asset, both on a per- postgraduate studies in some other areas a dog and publishing some fiction are sonal and professional level. of physics, or taking a second degree in also in my plans.

The Messenger 150 – December 2012 73 Astronomical News

Presenting the ESO Story: One Hundred and Fifty Messengers

Claus Madsen1 four telescopes in operation (including age, the editor was assisted by “local the 40-centimetre Grand Prism Objectif), correspondents” in Geneva and Santiago. in addition to two national telescopes, Interestingly, astronomy was absent, 1 ESO ESO had an active user community. Dur- at least as a science. This would soon ing that year, 178 observing runs were change. carried out with the ESO telescopes. Since 1974, The ESO Messenger has ­Furthermore, 14 runs were undertaken With the publication of issue No. 4, been one of ESO’s primary communica­ under ESO time with the national tele- astronomy entered the pages of The tion channels to the outside world in scopes. Perhaps more importantly, the Messenger. Intended to appear on a particular. It has provided a window not user community was preparing itself quarterly basis, this issue was published only onto the organisation, its projects and eagerly looking forward to the advent in March 1976, after an interruption of and people, but also onto the research of the 3.6-metre telescope. one year. In the meantime, the editorship carried out by ESO’s ever-growing had passed to Richard West. In 1975 user community. Last but not least, The Messenger was not the first pub­ a new Director General (DG), Lodewijk today it constitutes a fascinating histori­ lication by ESO. Aside from the Annual Woltjer, had taken over from Blaauw. cal source, documenting the life and Re­ports, ESO had published the ESO Woltjer was intent on strengthening the evolution of ESO over the last 38 years. Bulletin, the first issue appearing in scientific aspects of ESO including build- November 1966 and the last, No. 12, ing up a group of active scientists at published in June 1975. The Bulletin’s ESO. The editorial changes that may have “With this issue, we launch The ESO intended readership were astronomers seemed to begin rather subtly with issue Messenger in its orbit and wish it a fruit- and decision makers, but despite this, No. 4 fitted well within the overall direc- ful mission.” Such were the opening it had been a more modest undertaking tion of ESO under the new DG. West was remarks by ESO Director General Adriaan than The Messenger as regards size based in Geneva and thus embedded Blaauw, when the first six-page issue of and frequency, and it clearly covered a in the growing technical and scientific ESO’s new in-house magazine appeared much more restricted range of topics environment, rather than in the ESO in May 1974. The new publication was in the area of science and technology. administration, still based in Hamburg. As supposed to serve two purposes: a) “to The presentation style of the Bulletin was early as the following issue, astronomy promote the participation of ESO staff formal, rather different from the more had become the dominant topic, clearly in what goes on in the Organisation, relaxed ways of the new magazine. How- demonstrated by the fact that for the especially at places of duty other than ever, as The Messenger changed its first time, the cover page contained an our own”; and b) “to give the world out- character, the ESO Bulletin became re­­ astronomical picture of the globular clus- side some impression of what happens dundant and the articles that would have ter NGC 1851. The issue also featured inside ESO. appeared in this publication were now articles by astronomers describing their published in the new magazine. research. This was originally meant to At the time, the need for internal commu- motivate the non-astronomical staff at nication had become pronounced. In ESO. 1974, ESO had ongoing operations at Finding its feet four sites: the Headquarters in Hamburg; Newsletter-style reporting continued, the CERN premises which housed the The first issue ofThe Messenger, edited especially regarding the 3.6-metre ESO Telescope Project Division; Santiago- by Francis Walsh, was rather small, ­telescope, which was rapidly approach- de-Chile with its administrative and tech- with just six pages. Written in English, ing first light, but elaborate descriptions nical staff; and, of course, the La Silla selected texts were also reproduced in of staff barbecues, presentations of Observatory with its growing number of Spanish, mainly for the benefit of the staff representatives and the like disap- telescopes. Two decades before the local staff in Chile. The print run was 1100 peared. Even so, the editor tried to bal- worldwide web came into being and copies (Kjär, 2000), printed in letter-press, ance the scientific or technical articles e-mails became the standard communi- as was the custom of those days. Even with light and easy-to-read stories of gen- cation tool, maintaining proper com­ with six pages, the magazine included eral interest. In the early years, The munication and ensuring that staff was a wide range of “stories” from the “prepa- ­Messenger even published letters to the duly informed and motivated was an ration of a conference on Research editor, such as the following in the immense task, even if the ESO staff com- ­Programmes for the New Large Tele- December 1979 issue, allegedly from a plement was much smaller than today. scopes”, progress reports regarding the certain “H.D.”: “Since The Messenger 3.6-metre telescope project, the ESO is evolving in the direction of serious jour- The new magazine therefore reflected a Sky Survey, etc. to a short article about nals, one should consider the problem very real need, contributing to the coher- the ESO Christmas party, held in the of quoting articles in lists of references. ence of the organisation at a time when [Santiago] Guesthouse garden. The writ- The other day I found the reference: it was thinly spread and struggling under ing style and the choice of topics were ‘ESO Mess’ — which is perhaps not the the burden of completing the 3.6-metre reminiscent of a newspaper — or a best compliment to the otherwise fine telescope project. Reaching out beyond newsletter, which was precisely its in­­ organisation….” the ESO staff was equally important. With tended role. To ensure adequate cover-

74 The Messenger 150 – December 2012 Figure 1. The changing face of The Messenger – from a modest black and white version to the current appearance.

A particularly amusing article, written created by Karen Humby (No. 12); an only. Unsurprisingly, it was blue, intended by the editor and also published in example of the latter was a drawing by to match the official colour of the organi- December 1979, discussed the transfor- the iconic Danish cartoonist Robert sation (although it never really did). mation of observing, from the classical Storm Petersen, published in issue No. style with the astronomer glued to the 47. With police officers crowding an In terms of preparing the publication, eyepiece, patiently guiding his telescope observatory dome, the text explains that West formed a strong partnership with for an hour or more, to the modern auto- “the police now collaborate with the Kurt Kjär, who as technical editor over- mated (as it was described) mode of astronomers to determine the exact time saw the layout, typesetting and general observation. Reading this dark-humoured when bicycle lights must be lit”. interaction with the printers as well as the preview of the times to come is strongly distribution. Kjär remained as technical recommended, perhaps especially for The change of editor was also visible in editor until his retirement in 2003 (the last young astronomers. other ways. From issue No. 4, the banner issue on his watch was No. 111). West’s on the cover, designed by Bernard influence on the magazine was also visi- The editor also allowed space for the Dumoulin and featuring a stylised map of ble when it came to its size, occasionally occasional cartoon, in most cases pro- Europe and South America transposed reaching 40 pages during his first term. vided by gifted ESO staff, but also from on a starry sky, was printed in colour. (In 1980, West was succeeded as editor professionals. Perhaps most famous Since colour printing was expensive, this by Philippe Véron, only to return again of the first category was the cartoon of was the only use of colour and, modesty between 1986 and 1993 after finishing his the overcrowded La Silla Observatory, prevailing, the header used one colour term as IAU Secretary General). The

The Messenger 150 – December 2012 75 Astronomical News Madsen C., Presenting the ESO Story: One Hundred and Fifty Messengers

growth in the number of pages reflected article in March 1998 by the Director Gero Rupprecht’s summary of 20 years the increase in activities at ESO and within General of the time, Riccardo Giacconi, of FORS operations (No. 140), and indeed the scientific community. It is therefore entitled “The Role of ESO in European many others. not surprising that The Messenger would Astronomy”, in which he laid down the also continue to grow, reaching a peak of rationale for the organisation within Since the early days, The Messenger 88 pages in December 1992. the European astronomical landscape, had brought articles about new tele- setting the course for future projects. scopes and instruments, and it could be But the use of The Messenger as a stra- said that these articles stand out as the History, current affairs and preview of the tegic communication tool was perhaps strongest contemporary asset of the future most clearly enunciated in No. 100, pub- publication. This is hardly a coincidence. lished in June 2000, which fittingly pre- The strong engineering tradition is one Among the many pages, thousands by sented the 100-metre Overwhelmingly of the hallmarks of ESO and undoubtedly today, it is difficult to pinpoint articles Large Telescope (OWL) conceptual study a key source behind its success. of particular importance, but it is hard to to the audience of readers and helped overlook the series of papers that to prepare the ground for the coming ELT In September 1993, Marie-Hélène Ulrich appeared in Nos. 15 and 16 (December generation of telescopes. On the cover took over as editor of The Messenger. 1978 and March 1979) under the com- page of the anniversary issue, just above The change of editorship brought a tight- mon heading “Ten nights at the VLT”. the OWL paper, the editor presented ening of the editorial policies, with an Here prominent astronomers offered their The Messenger as “one channel of ESO’s introduction of fixed sections on Tele- views and expectations as regards multimedia approach to providing infor- scopes and Instrumentation, Reports Europe’s next generation telescope, the mation about its activities and achieve- from Observers and Other Astronomical Very Large Telescope (VLT), at the time ments”. News and finally, Announcements. This barely more than a dream. This was a change enforced the move towards a year after the seminal ESO conference at This shift in approach did not mean that publication for technically or scientifically CERN about the large telescopes of The Messenger no longer maintained its oriented readers. The more rigid ap­­ the future, which in many ways started ­mixture of articles, including institutional proach, manifested in the new format, the thinking about the VLT. This shows a developments, new instruments and was maintained by Ulrich’s successor, different aspect of The Messenger that ­current observation programmes. It was Peter Shaver, who assumed the task gradually began to evolve – beyond news- sometimes even used for fast presen­ in June 2002. At the time, opening up paper-style reporting and educational tation of new research results, although The Messenger to cover non-ESO related articles about astronomical research to without a peer-review system it never astronomical news was considered, the use of the magazine as a strategic aspired to become a formal scientific but in the end, The Messenger continued communication tool, supporting the over- journal. One strength of The Messenger on the path it had followed so far — as all future goals of the organisation. This was the short production time. An exam- an in-house publication appealing to a is visible again in the use of colour print- ple of this was a 16-page section with broad external readership. This reader- ing, until December 1982 restricted to the early ESO observations of SN 1987A, ship was sizeable. From the original print banner on the cover page. In the Decem- appearing only three weeks after its dis- run of little more than a thousand copies, ber 1982 issue, which celebrated the covery in February 1987. in the 1980–90s the circulation grew 20th anniversary of ESO, The Messenger to 3–5000, with an estimated readership featured the first tri-colour composite The Messenger also gave space to clearly exceeding that number since it in­­ images based on ESO Schmidt plates as ­retrospective articles. Best known, per- cluded many institute and public libraries. well as early CCD images in colour. haps, is the series of articles written by Adriaan Blaauw and published in One year later, in December 1983 (No. 34), 1990–91 about ESO’s early history, which Changing appearance the cover page had a large picture with he defined as the period between 1953 an artist’s impression of the VLT, created and 1975. These articles were subse- Looking back, the editorial changes can by Jean Leclercqz. The particular picture quently compiled into a book that has largely be seen as adjustments to the bears relatively little resemblance to the become the reference historical descrip- early concept, although compared to the VLT as we know it today, but it stirred the tion of ESO during that epoch (Blaauw, first issues there is little resemblance imagination of the readers, following 1991). But others provided informative between then and now. This also applies the crucial meeting in Cargèse, in which articles and brief notes about ESO’s his- to the graphical appearance, even though the project began to take shape with tory as well, such as Daniel Enard’s for almost 30 years, practically no visi- the support and enthusiasm of the astro- “The VLT – genesis of a project” in issue ble changes occurred. On the technical nomical community. The same issue No. 50, Woltjer’s article on the “Discovery side much had happened. Thus, from ­carried an article by Daniel Enard and of Paranal” (No. 64), Alan Moorwood’s issue No. 6, offset printing was used and Jean-Pierre Swings about the project. article on the evolution of infrared instru­ from issue No. 79 (March 1995), desktop mentation at ESO over 30 years, appear- publishing was introduced. By March Perhaps an article of similar importance ing in the same issue as Hans Dekker’s 2003, however, the new technical editor, to the VLT “dreams” of the 1970s was the paper on optical spectrographs (No. 136), Henri Boffin, had given the magazine a

76 The Messenger 150 – December 2012 face-lift. The first change was the intro- access to past issues, from the very first unwittingly, however, it has fulfilled an duction of full-size cover pictures (i.e. issue until today. In that sense, one of additional role as a highly valuable source with no text other than a caption). A year the two aims for the magazine when it of information about ESO’s history and, later, the traditional banner at the top was launched 38 years ago – to provide to the extent that it mirrors at least some of the cover disappeared, seeing instead a window onto ESO for the outside world main developments and trends in the the introduction of the row of flags of — has un­doubtedly been reached. general history of European astronomy, it ESO’s member states. The other aim, to support internal com- remains an incredibly rich treasure to munication (although it was phrased explore and to enjoy. Happy Anniversary, When Boffin moved to other tasks at ESO slightly differently) can be said to have Messenger! in March 2005, Jutta Boxheimer re- been reached as well, inasmuch as the placed him as technical editor. Boxheimer publication contains a wealth of informa- brought with her the skills of a very tion about what goes on at ESO at the Acknowledgements ­successful, professional graphic designer technical level. Providing space for the The author wishes to thank Kurt Kjär and Richard with additional solid experience in scien- members of the science faculty to pre- M. West for informative discussions in connection tific publishing. She naturally played a sent themselves has added an important with the preparation of this article. central role in developing the new ESO human dimension, too. Nonetheless, the “corporate design” which encompassed relaxed newsletter, as it was originally Editors Technical Editors everything from letterheads and busi- conceived, has disappeared. So has the 1974–1975 Francis Walsh Kurt Kjär ness cards to the ESO website – and, of Spanish summary, which was discon­ 1976–1980 Richard West Kurt Kjär course, The Messenger. From then on, tinued in March 1988, although two arti- 1980–1986 Philippe Véron Kurt Kjär ESO’s communication efforts, including cles, in much abbreviated versions, 1986–1993 Richard West Kurt Kjär the graphical design, were seen as a appeared slightly later. The last one, with 1993–2002 Marie-Hélène Ulrich Kurt Kjär whole, establishing The Messenger in its the title, “Mi Visita a La Silla”, fittingly 2002–2006 Peter Shaver Kurt Kjär present look and feel and supporting described a visit to the observatory by Henri Boffin its image of a mature, up-to-date, serious André Muller, the ESO Superintendent in (from 2003) scientific publication with high quality Chile of the early years. This article was Jutta Boxheimer (from 2005) content. published in December 1988. 2007– Jeremy Walsh Jutta Boxheimer The current external circulation, of The Messenger has over the years 4100 copies, is testimony to the contin- served several purposes: as a tool for References ued in­terest that readers take in ESO internal communication as well as provid- Blaauw, A. 1991, ESO’s Early History — The and its activities. In the recent years, ing information to the user community European Southern Observatory from Concept The Messenger has also been accessible at large and other interested parties, such to Reality. ESO, Garching, Germany online and so even new readers have as many amateur astronomers. Perhaps Kjär, K. 2000, The Messenger, 100, 53 Credit: ESO/IDA/Danish m/R. 1.5 Gendler and Thöne C.

A colour image of the nearby barred spiral galaxy NGC 4945, in the Centaurus A group of galaxies, obtained with the 1.5-metre Danish telescope at La Silla. Images in three filters (B-, V- and R-bands) were combined and emphasise the dust clouds and H ii regions of the disc. In the centre of the galaxy there is a heavily obscured Seyfert 2 active galactic nucleus. More details can be found in Picture of the Week 15 February 2010.

The Messenger 150 – December 2012 77 Astronomical News

Announcement of the ESO Workshop The Deaths of Stars and the Lives of Galaxies

8–12 April 2013, ESO Vitacura, Santiago, Chile

Too often in astronomy, experts from vari- – What is the source of carbon in the ous fields do not interact, making pro- Universe? gress slower than it could be. This is why – What are the Type i a supernova pro- it is sometimes useful to come together genitors? in a workshop that embraces a larger scope than traditional ones. This ESO A remarkable panel of invited speakers workshop will do precisely that, bringing will provide extensive reviews of the three together astronomers working on the themes, while still leaving plenty of time final stages of stellar evolution and how available for contributed talks and discus- their demise affects their immediate sur- sions. roundings and their host galaxies. The deadline for abstract submission is The conference is organised along three 31 January 2013 and registration will broad themes: channels of stellar death, be open until 28 February 2013, or until products of stellar death, and stellar we have reached the maximum number death in an extragalactic context. It will of participants. address questions such as: – Which stars become planetary nebulae? Details are available at: – What are under-energetic supernovae? http://www.eso.org/dslg2013/ – Where is the dust in the Universe com- or by e-mail: [email protected] ing from?­

Personnel Movements

Arrivals (1 October–31 December 2012) Departures (1 October–31 December 2012)

Europe Europe Geier, Stephan (D) Fellow Aspinall, Gareth (GB) Project Planner Gibson, Neale (GB) Fellow Clare, Richard (GB) Physicist Grunhut, Jason Harley (CDN) Fellow Grosbøl, Preben (DK) Systems Scientist Huckvale, Leo (GB) Student Heyer, Hans Hermann (D) Photographer Inno, Laura (I) Student Krüger, Anna (D) Adminstrative Assistant Lagos Urbina, Claudia del Pilar (RCH) Fellow Maury, Anaelle (F) Fellow Rahoui, Farid (F) Fellow Meuss, Holger (D) Software Engineer Urrutia-Viscarra, Paula Maria Fernanda (RCH) Student Montagnier, Guillaume (F) Fellow Wang, Ke (VR) Fellow Vernazza, Pierre (F) Fellow Woillez, Julien (F) Instrument Scientist Zinsmeyer, William (USA) Software Engineer Yan, Fei (VR) Student

Chile Chile Aladro, Rebeca (E) Fellow Camuri, Massimiliano (I) Lead Electrical Engineer Blanchard, Israel (RCH) Telescope Operator Fulla Marsa, Daniel (E) ALMA Commissioning Scientist Breitfelder, Joanne (F) Student Gourgeot, Florian (F) Student Dias, Bruno (BR) Student Jones, Matias (RCH) Student Elliott, Paul (GB) Student Kim, Taehyun (ROK) Student Gonzalez Garcia, Oscar Alberto (RCH) Fellow Macchino, Agustin (RCH) Electronics Engineer Grellmann, Rebekka (D) Fellow Marti Canales, Javier (E) Lead System Engineer Krogager, Jens-Kristian (DK) Student Pizarro, Manuel (RCH) Telescope Instruments Operator Milli, Julien (F) Student Wahhaj, Zahed (BD) Operations Astronomer

78 The Messenger 150 – December 2012 Astronomical News

Vistas de la Galaxia

The recently released book Vistas de the central ~ 315 square degrees of la Galaxia (Vistas of the Galaxy) by Dante the Galaxy, featured on p. 44–45 and in Minniti, Joyce Pullen and Ignacio Toledo Release eso1242. describes some of the discoveries of the VISTA Variables in the Via Lactea (VVV) public survey being conducted References with the Visible and Infrared Survey Tele- Minniti, D., Pullen, J. & Toledo, I. 2012, Vistas de la scope for Astronomy (VISTA). Galaxia, Ograma Impresores, Santiago Saito, R. K. et al. 2010, The Messenger, 141, 24

Pontificia Universidad Católica de Chile/ESO VVV is a near-infrared survey of the Saito, R. K. et al. 2012, A&A, 544, 147 Galactic Bulge, including the monitoring of many variable stars, to determine the structure and properties of the central 520 square degrees of the Galaxy. The PI is Dante Minniti of Pontificia Universi- dad Católica de Chile. The survey was described in Saito et al. (2010). One of the recent results from this survey (Saito et al., 2012) is the 84-million-star colour– magnitude diagram and density map of

DVD of Europe to the Stars

To celebrate its 50th anniversary year, ESO has released the documentary Europe to the Stars — ESO’s first 50 years of Exploring the Southern Sky. The DVD is included here with this 150th issue of The Messenger.

The movie consists of eight chapters each focusing on an aspect of ESO Observatories and is presented by Joe Liske (Dr J). The running time is 63 min­ utes and includes bonus material. The narration language is English and there are subtitles in 20 languages.

The Messenger 150 – December 2012 79 ESO, the European Southern Observa­ Contents tory, is the foremost intergovernmental astronomy organisation in Europe. It ESO 50th Anniversary is supported by 15 countries: Austria, T. de Zeeuw – A Milestone for The Messenger in ESO’s 50th Anniversary Year 2 Belgium, Brazil, the Czech Republic, L. Woltjer, H. van der Laan, R. Giacconi, C. Cesarsky – Reflections from Denmark, France, Finland, Germany, Past Directors General 3 Italy, the Netherlands, Portugal, Spain, R. Sirey – ESO 50th Anniversary Gala Dinner 7 Sweden, Switzerland and the United Kingdom. ESO’s programme is focused Telescopes and Instrumentation on the design, construction and opera­ F. Patat, G. Hussain – Growth of Observing Programmes at ESO 17 tion of powerful ground-based observ­ E. Brinks et al. – Report of the ESO OPC Working Group 21 ing facilities.­ ESO operates three obser­ R. Schödel, J. H. Girard – Holographic Imaging: A Versatile Tool for High vatories in Chile: at La Silla, at Paranal, Angular Resolution Imaging 26 site of the Very Large Telescope, and H. Kuntschner et al. – The ESO 3D Visualisation Tool 30 at Llano de Chajnantor. ESO is the European partner in the Atacama Large Astronomical Science Millimeter/submillimeter Array (ALMA) C. Baltay et al. – The La Silla–QUEST Southern Hemisphere under construction at Chajnantor. Variability Survey 34 ­Currently ESO is engaged in the design A.-M. Lagrange, G. Chauvin – β Pictoris, a Laboratory for Planetary of the European Extremely Large Formation ­Studies 39 ­Telescope. P. Kervella et al. – RS Puppis: A Unique Cepheid Embedded in an Interstellar Dust Cloud 46 The Messenger is published, in hard­ M. Tewes et al. – COSMOGRAIL: Measuring Time Delays of copy and electronic form, four times Gravitationally Lensed Quasars to Constrain Cosmology 49 a year: in March, June, September and M. Bradač et al. – Breaking Cosmic Dawn: December. ESO produces and distrib­ The Faintest Galaxy Detected by the VLT 53 utes a wide variety of media connected­ J. Wagg et al. – Early ALMA Science Verification Observations of to its activities. For further information, Obscured Galaxy Formation at Redshift 4.7 56 including postal subscription to The L. Testi et al. – Science Verification Datasets on the ALMA Science Portal 59 Messenger, contact the ESO education and Public Outreach Department at the Astronomical News following address: G. Meylan, M. Steinacher – Switzerland Celebrates 30 Years of ESO Membership 63 ESO Headquarters J. Walsh et al. – Report on the Workshop Karl-Schwarzschild-Straße 2 “ESO@50 — The First 50 Years of ESO” 64 85748 Garching bei München M. Rejkuba, M. Arnaboldi – Report on the Workshop Germany “Science from the Next Generation Imaging and Spectroscopic Surveys” 67 Phone +498932006-0 D. Baade – Retirement of Preben Grosbøl 69 [email protected] Announcement of the “ESO Public Survey Catalogue for Ultra-VISTA available from the Science Archive Facility” 70 The Messenger: Staff at ESO – P. Gray 71 Editor: Jeremy R. Walsh; Fellows at ESO – N. Kains, R. Galván-Madrid 72 Design, Production: Jutta ­Boxheimer; C. Madsen – Presenting the ESO Story: One Hundred and Fifty Messengers 74 ­Layout, Typesetting: Mafalda Martins; Announcement of the ESO Workshop Graphics: Roberto­ Duque. “The Deaths of Stars and the Lives of Galaxies” 78 www.eso.org/messenger/ Personnel Movements 78 Vistas de la Galaxia 79 Printed by G. Peschke Druckerei GmbH, Schatzbogen 35, 81805 München, Germany Front cover: The Wolf–Rayet Nebula NGC 2359, known as the Thor’s Helmet ­Nebula, is shown in a colour image from VLT FORS2 exposures in B-, V- and R-bands. Unless otherwise indicated, all images This image was released on 5 October 2012 for the 50th anniversary of the founding in The Messenger are courtesy of ESO, of ESO and was taken with the help of a member of the general public, Brigitte except authored contributions which ­Bailleul — winner of the competition Tweet Your Way to the VLT!. The nitrogen-rich are courtesy of the respective authors. nebular bubble surrounds the WN4 star HD 56925 and is blown by the prodigious mass loss of this Wolf–Rayet star. The wind from the star is ­interacting with an ambi­ © ESO 2012 ent cloud to the east and south, driving shock fronts into the cloud giving rise to ISSN 0722-6691 molecular emission. More details can be found in Release eso1238.