Scientific Strategy Planning at ESO © ESO

SSCIENTIFICCIENTIFIC SSTRATRATEGYTEGY PPLANNINGLANNING AATT ESOESO

INTRODUCTION BY RALF BENDER, CHAIR OF THE SCIENTIFIC STRATEGY WORKING GROUP

At its 100th meeting in June 2003, the ESO Bender (Chair), Tim de Zeeuw, Claes Frans- tific goals and objectives. To this end, current Council decided to install a Working Group son, Gerry Gilmore and Franco Pacini; Bruno and future developments and the possible to discuss ESO’s scientific strategy until Marano and members of the STC, the implications of further external collaboration 2020. The time appeared ripe to discuss VLTI Implementation Committee and the and enlarged membership may also be con- the future, as the VLT was now largely com- European ALMA Board: Jean-Loup Puget, sidered.” pleted, ALMA had just been approved, and Thomas Henning, and Simon Lilly. ESO was The Working Group met three times and the ESO community had been significant- represented by Bruno Leibundgut, Guy Mon- prepared a report accompanied by a set of ly strengthened by the recent accession of net and Peter Quinn. The Director General recommendations. After minor revisions, the the United Kingdom. Furthermore, the dis- and the Head of Administration attended all ESO Council adopted the recommendations cussions and concept studies for the next meetings as well. as a formal “Council Resolution on Scientific large facilities (notably the Extremely Large The charge to the Working Group was Strategy” in its last meeting in December Telescopes) were underway world-wide. Evi- defined by Council as follows: “Prepare and 2004. Both documents are printed below. dently, it was important to develop a strategy assess the options for ESO’s long term pro- I take this opportunity to thank all Work- for ESO’s future now. gramme, taking a broad view of ESO’s role ing Group members for very good and open The Scientific Strategy Working Group in world astronomy [...]. In doing so, the discussions, constructive contributions and was composed of members of Council: Ralf Group shall consider ESO’s long term scien- pleasant and efficient meetings.

REPORT FROM THE WORKING GROUP ON SCIENTIFIC STRATEGY PLANNING

INTRODUCTION and stars throughout 90 % of the age of the until today, (iv) extreme conditions of matter 1. ESO’s mission was stated in the Con- universe. We have found supermassive black and energy (e.g. black holes), (v) the forma- vention as to “establish and operate an holes in most galaxy centres and have probed tion of stars and planetary systems, and (vi) astronomical observatory in the southern their evolution to high redshifts. We have the characterization of extra-solar planets in- hemisphere, equipped with powerful instru- seen the seeds of galaxies and their large- cluding the search for extraterrestrial life. ments, with the aim of furthering and orga- scale distribution in the cosmic microwave 7. Addressing all of these questions re- nising collaboration in astronomy”. In the background. We have determined the cosmic quires a co-ordinated observational and ex- current world and in view of Europe’s and parameters with an order of magnitude better perimental approach, spanning all wave- ESO’s achievements in astronomy in the last accuracy. We have confirmed the existence lengths of the electromagnetic spectrum with decade, ESO’s mission could be stated more of dark matter which is 5 times more abun- facilities on the ground and in space but also ambitiously: ESO should provide European dant than ordinary matter, and we have found exploring new observing windows to the uni- astronomers world-class facilities to pursue that the universe is filled to 70% with the verse, like underground neutrino detectors, the most fundamental astronomical ques- so-called ‘dark energy’, a new state of ener- or space interferometers for gravitational tions. gy of hitherto unknown nature. And last, not wave detection. Ground-based astronomy 2. ESO cannot do this alone. A close least, we have, for the first time, found plan- with large aperture telescopes plays a pivotal partnership between ESO and the astronomi- ets around other stars. role in the overall concept because (a) most cal institutions in its member countries is cru- 5. It is evident that progress in astronomy sources we want to study emit a large frac- cial to the development and preservation is driven by both unexpected discoveries tion of their radiation between optical and of the scientific and technical excellence (e.g. dark matter, dark energy) as much as radio wavelengths, (b) this wavelength range of European Astronomy. This implies that by particular experiments designed to test provides crucial and detailed information the success of European Astronomy relies specific theories (like ongoing microwave about the physical nature of the sources, and equally on a world-class ESO and on strong background experiments). Astronomical dis- (c) the sources we want to study are general- and active research institutions throughout coveries are often made by pushing the lim- ly very faint. In addition, large telescopes like Europe. its of observation with the most powerful tele- Keck and VLT have not only made important 3. The granting of access to ESO facilities, scopes on the ground and the most advanced discoveries by themselves but also have participation in ESO programmes, and even satellites in space (e.g. high redshift galax- provided crucial complementary information membership of ESO are based primarily on ies, black holes, gamma ray bursts etc), but to discoveries made with satellites (e.g. scientific excellence. ESO will continue to be smaller workhorse telescopes and instru- the Hubble Space Telescope, ISO, Chandra open to new members and collaborations, fol- ments used in a new mode of operation can etc.) which otherwise could often not be inter- lowing the principles of furthering excellence also produce very exciting discoveries (e.g. preted comprehensively and would remain and scientific cooperation. MACHOS, planets etc.). inconclusive. And finally, beyond their 6. Key scientific questions in astronomy large light collecting power, the additional THE ASTRONOMICAL FRAMEWORK and astrophysics over the next 20 years will strengths of ground-based telescopes are 4. Over the past two decades, Astronomy include (i) the nature of dark matter, (ii) the their high versatility and the possibility to has entered its golden age. A few examples nature of dark energy, (iii) the formation of explore new technologies rapidly. of what has been achieved are: We have now the very first stars and galaxies and follow- 8. Astronomy has from its very beginning direct evidence for the evolution of galaxies ing their evolution from the highest redshifts been a technology-enabled science and is 2 The Messenger 119 View of La Silla from THE EXTREMELY LARGE TELESCOPE the 3.6 m telescope. 15. The unique capabilities of an Extreme- ly Large Telescope (30 m and larger) are (i) its 16 to 160 times larger light collecting power than a VLT UT and (ii) its potentially 10 to 40 times higher spatial resolution than the Hubble Space Telescope. The combination of these two features will enable imaging and especially spectroscopy of sources up to a factor 50 fainter than currently possible. Considering the enormous progress the Hubble Space telescope brought with its factor 10 improvement in spatial resolution, and the 8 m class telescopes with their factor 5 in light collecting power, the discovery power and impact of an ELT can hardly be overes- now progressing more rapidly than ever to be reconsidered and more specialization timated. With an appropriate choice of the site before, with its technology feedback benefit- may be required. an ELT should also offer unique imaging ing industry. In ground-based astronomy, 12. The VLTI is acknowledged to be the capabilities in the sub-mm range comple- improving the performance of existing tele- most advanced interferometer in the world menting ALMA. scopes and the construction of the next gen- in almost all aspects (except nulling interfer- 16. The case for an ELT alone is compel- eration of telescopes and instruments will ometry with Keck). It will be the best sys- ing; in the context of other facilities it is over- require investment in several critical tech- tem to enable faint science (e.g. structure of whelming. An ELTwill be an important com- nologies. Important over the next 10+ years Active Galactic Nuclei) and ground-based plement to ALMA, the James Webb Space will be, e.g., the development of multi-con- astrometry, because it is the only system Telescope (JWST), future space missions like jugate adaptive optics, laser guide stars, that can potentially combine four 8 m tele- DARWIN and XEUS, and to other space and the mastering of increasingly complex telescopes interferometrically. The VLTI is still ground observatories. It is important to real- scope/instrument systems and the handling being constructed, with new instruments to ize that, because of their intrinsically differ- and exploration of Petabytes of data. be added and four Auxiliary Telescopes to be ent capabilities, ELTs on the one hand and completed. space missions like DARWIN or JWST on ESO’S FACILITIES 13. ALMA will open a new window to the the other hand, will not compete but rather 9. ESO and its collaborating institutes universe and provide unprecedented access support each other by providing complemen- have a highly skilled and very motivated staff to the gaseous medium and the star formation tary information about planets, stars and gal- specialized in the design, construction and processes both in our Galaxy and in the most axies. In combination, these facilities will operation of large optical/IR telescopes and distant galaxies in the universe. ALMA will produce the next revolution in our under- their instruments. Another major strength of discover vast numbers of faint sources that standing of the universe and its constituents. ESO is the efficient management of large require complementary observations at other 17. The scientific reach of an ELT, and its projects which is one reason why the VLT is wavelengths. potential for making new discoveries, are so the best ground-based astronomical facility 14. These facilities, and many others great that there is a strong case for each of the today. It took decades to build this expertise around the world, produce an enormous world’s regions having access to an ELT. Col- and this asset must be preserved if Europe is amount of archived data which is avail- laborative efforts should be encouraged, but to stay competitive in the future. ESO has also able to the astronomical community. ESO is should not be allowed to compromise Euro- managed its facilities effectively, opening a working with European institutions in a glo- pean access to an ELTor to its associated tech- new site for the VLT because it was scien- bal effort to establish an International Virtu- nological benefits. It is therefore important tifically advantageous to do so, and closing al Observatory. This project addresses criti- that European astronomy builds on its current facilities on La Silla when no longer scien- cal requirements for handling the steadily strength and aims for a leading role in the tifically cost effective. increasing data rates from ESO telescopes development and construction of an ELT. 10. La Silla is still one of the most and for connecting them with data sets This is also vital in attracting the best young successful observatories world-wide. Survey obtained by other facilities and at other wave- scientists and keeping them in Europe. North and monitoring projects with dedicated in- lengths. Data handling and processing is one American institutions (CalTech, UC, AURA, struments (e.g. HARPS for planets) have of the key new challenges in astronomy. Canada) are undertaking a detailed design become increasingly important and produce impressing scientific results. La Silla has also been needed to provide targets for the VLT. However, with the installation of VST/OmegaCAM and VISTA, preparatory observations and target finding for the VLT will not have to rely on La Silla beyond 2006. 11. The VLT is the most powerful and ver- satile 8 m telescope system to date. It is now fully operational. Further upgrades and the development of second generation instruments should ensure European leadership in most areas of optical/IR astronomy for at least 10 more years. Once a 30 m+ telescope and the James-Webb-Space-Telescope The VLT with go into operation, the role of the VLT needs stations of the VLTI (foreground). © ESO – March 2005 3 study of a 30 m telescope, the TMT. Another Scenario Telescope Phase B Phase C/D Start of science Full completion group of institutions (led by Carnegie Ob- diameter starts starts (partially filled) servatories) has started constructing a 21 m I 100 m 2005 2007 2012 (50 m dia.) 2016 telescope, the GMT. Their ambition is to have II-100 100 m 2006 2010 2017 (60 m dia.) 2021 first light before 2016 for both projects. II-60 60 m 2006 2010 2016 (40 m dia.) 2020 Europe must keep pace with this work. 18. ESO and European Institutions are the highest level to remain attractive for the which consequently must have higher prior- jointly pursuing technology development and best scientists and engineers. This means that ity than the continued operation of La Silla. concept studies towards an ELT (in part Europe, and specifically ESO, must partici- 26. The European components of ALMA through the FP6 framework). ESO has devel- pate in the most important and challenging are being constructed in collaboration with oped what appears to be the most innovative technical and scientific developments of the institutes within the European astronomical concept to date for an Extremely Large Tele- future and should set priorities accordingly. community. This collaboration is also critical scope, namely the OWL1. The OWL concept This is also important for European indus- for the development of adequate data analy- studies have been carried out in close col- tries. sis tools which will help to educate European laboration with industry and indicate that a 22. In the different scenarios for ESO’s astronomers to make best use of ALMA and fundamentally new approach to build large future until 2015, optimal support for the VLT perform cutting-edge science projects. ESO telescopes should allow the construction of and ALMA and the development of an ELT should build up sufficient competences in the a 60 m telescope for a cost comparable to are unquestionable priorities. The operation mm and sub-mm fields to coordinate and that of a conventional 30 m telescope. The of La Silla and the enhancement of VLTI can complement the expertise and support from new paradigm is based on the adoption have different priorities. outside institutions. of serialised industrial production and a fully 23. The success and excellence of Euro- 27. ESO must ensure that Europe pre- computer-controlled optical system to reduce pean astronomy requires ESO to maintain serves its current world-leading position cost without compromising performance. the VLTas a world-leading facility for at least into the ELT era, because ESO and European Below about 60 m, the OWL concept prob- 10 more years. The VLT needs constant up- astronomers cannot afford to be left be- ably loses its high cost effectiveness. A grading, including MCAO and an adaptive hind in the most important developments detailed design study is essential to validate secondary, and a vigorous 2nd generation in ground-based optical/IR astronomy. This the OWL approach, including instrumen- instrument program because ESO must: can be achieved through the construction tation, and establish the optimal balance a. keep pace with the steadily improving of a 60 m OWL for a cost comparable to a US between science, technology, and cost. capabilities of other 8 m telescopes (Keck, 30 m telescope. Thanks to its new concept 19. The total cost for a 100 m ELT based Gemini, Subaru, LBT …), based on serialised production, an OWL-type on the OWL concept is currently estimated to b. continue to utilise technological ad- telescope can be realized at much lower cost be about 1200 M Euros. A 60 m ELT would vances, than a ‘conventional’30 m telescope of Keck- cost about half this amount, or roughly the c. match the evolving European science re- design. However, the advantages of serialised cost of VLT or ALMA. quirements, and production only become effective beyond 20. Three illustrative scenarios have been d. maintain developments that are critical for about 60 m and are in fact being validated developed by ESO. They are not yet opti- an ELT. for a 100 m telescope. mised for cash flow or resource usage, but are 24. The unique capabilities of the VLTI 28. One of the advantages of the ESO sufficient to illustrate the main points in the mean that the current generation of VLTI conceptual design is that the telescope is de- planning. While still including some allo- instruments and PRIMA for two telescopes signed so that it can be ‘staged’ in diameter, cation for technological development in should be completed with high priority. The becoming available for observations with crucial areas, Scenario I corresponds to the case for the extension of PRIMAto four beam only a partially completed primary mirror. An fastest schedule technology could plausibly combination using either 4 ATs or 4 UTs needs OWL-type telescope could have first-light as allow. Scenario II-100 allows more extensive to be demonstrated with simulations of real- a 30 m telescope on a competitive timescale design and development periods before start istic observing situations. If the demonstra- and then grow to a 60 m over several addition- of construction, and a relaxed integration tion is convincing, four beam combination al years (the ALMA project already adopts schedule. Scenario II-60 corresponds to a should be implemented. the same philosophy), and similarly a 100 m 60 m instead of a 100 m telescope. 25. The role of La Silla beyond 2006 has telescope could start operations as a 50 m or been cogently presented. La Silla will still be 60 m. Similarly, Europe can stay competi- CONCLUSIONS useful and competitive in many respects, but tive in timescale by adopting this ‘growing a 21. Over the last decade ESO has suc- it will not be as essential for the success of telescope’ concept and so having access to ceeded in becoming fully competitive and ESO as the VLT, VLTI, ALMA and an ELT a world class 30 m telescope at the same time indeed world leading. However, the risk of falling back is real, even in the near future, especially with respect to ELTs. To maintain its position Europe has to adopt plans which keep its scientific and technical ambitions at

1 In this document, the term ELT refers to all telescopes larger than 30 m, without reference to a specific design. Most technology development that has been carried out up to now (e.g. within EU-funded projects) is at the component level and is indeed design independent. The term OWL is used only when referring to the specific telescope concept that has been developed by ESO. All the statements related to OWL in this document should be revisited after the conceptual de- Artist’s image of the sign review which is expected to take place at the Atacama Large Milli- end of 2005. meter Array (ALMA). 4 The Messenger 119 as the North American colleagues. Strong technologies in collaboration with the Euro- instruments, and data handling. To achieve community involvement for system level pean astronomical community and within the this goal, ESO should continue its very development and provision of instrumenta- framework of the International Virtual Ob- successful partnership with European astro- tion will, as in the case of VLT and ALMA, servatory Alliance. The availability of these nomical institutions and industries as in the be crucial for our success. technologies is an important factor for the past, also within the framework of EU fund- 29. As with ALMA, a collaboration with future success of ESO and European Astro- ed projects. North America and possibly others would nomy. enable an even more ambitious global ELT 31. Because astronomy and astrophysics project to be undertaken. exploit leading edge technology, ESO should 30. ESO should continue to develop new remain at the forefront of future mainstream data archiving, data access, and data mining and key technologies concerning telescopes,

Artist’s impression of ESO’s OWL concept.

ESO COUNCIL RESOLUTION ON SCIENTIFIC STRATEGY

ESO Council, considering the report of its – only the continued investment in cutting – the VLT will continue to receive effec- Working Group for Scientific Strategic Plan- edge technologies, telescopes, instruments tive operational support, regular upgrad- ning, ESO/Cou-990, and its recommenda- and information technology will enable ing (especially to keep it at the forefront tions in ESO/Cou-964 rev. 2, agrees that such scientific leadership and discoveries, in image quality through novel adaptive – ESO will continue to be open to new optics concepts) and efficient 2nd genera- – astronomy is in a golden age with new members and collaborations, following tion instrumentation in order to maintain technologies and telescopes enabling an the principle of furthering scientific excel- its world-leading position for at least ten impressive series of fundamental dis- lence, more years, coveries in physics (e.g. dark matter, dark – the unique capabilities of the VLTI will be energy, supermassive blackholes, extraso- and accordingly adopts the following princi- exploited, lar planets), ples for its scientific strategy: – the construction of an Extremely Large – over the last decade, the continued invest- Telescope on a competitive time scale will ment of ESO and its community into the – ESO’s highest priority strategic goal must be addressed by radical strategic planning, improvement of ground-based astronom- be the European retention of astronomical especially with respect to the development ical facilities has finally allowed Europe leadership and excellence into the era of of enabling technologies and the explo- to reach international competitiveness and Extremely Large Telescopes by carefully ration of all options, including seeking leadership in ground-based astronomical balancing its investment in its most impor- additional funds, for fast implementation, research, tant programmes and projects, – ESO and its community will continue their – the prime goal of ESO is to secure this sta- – the completion of ALMA is assured and successful partnership and seek effective tus by developing powerful facilities in conditions for an efficient exploitation of intercontinental collaborations in devel- order to enable important scientific dis- its superb scientific capabilities will be oping the most important and challenging coveries in the future, established, technologies and facilities of the future.