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The Messenger

No. 121 – September 2005

Science with Extremely Large Telescopes

Figure 1: Concepts for 50–100-m ELTs. Left: the OWL (Over Whelmingly Large) Telescope, a design for a 100-m-class telescope being developed by ESO (Gilmozzi 2004, Dierickx et al. 2004). Right: The Euro-50 concept (Andersen et al., 2003, 2004).

Isobel Hook (University of Oxford) In the past half-century a new generation scope (TMT). In Europe the focus is on and the OPTICON ELT Science of telescopes and instruments allowed even larger telescopes – preliminary stud- Working Group remarkable new discoveries: quasars, ies indicate that the technology to achieve http://www.astro-opticon.org/ masers, black holes, gravitational arcs, a quantum leap in telescope size is fea- networking/elt.html extra-solar planets, gamma ray-bursts, sible, and a detailed design study is now the cosmic microwave background, dark under way in Europe (led by ESO) to matter and dark energy have all been develop the technology needed to build a Astronomers around Europe are gearing discovered through the development of a 50–100-m telescope (see Figure 1). up for the next generation of ground- succession of ever larger and more based telescopes to follow on from the sophisticated telescopes. This progress A larger telescope is beneficial for two success of the VLT and other 6–10-m poses new, and more fundamental, main reasons – firstly, a larger collecting telescopes. All aspects of astronomy questions, the answers to some of which area (proportional to the square of the will be dramatically advanced by the will perhaps unite astrophysics with diameter) allows fainter and more distant enormous improvements attainable in elementary particle physics in a new ap- objects to be observed. Secondly, the collecting area and angular resolution: proach to the nature of matter, while resolution achievable improves in propor- major new classes of astronomical ob- others may give us insights as to the exis- tion to diameter of the telescope, projects will become accessible to obser- tence (or otherwise) of other life-sup- vided that the telescope is equipped with vation for the first time. In July of this porting planets in our Galaxy. As the cur- an adaptive optics system that corrects year a book1 was produced by a group rent generation of telescopes continues for the blurring effects of the Earth’s at- of European astronomers, which de- to probe the universe and challenge our mosphere. Thus a 50-m telescope work- scribes the science achievable with a understanding, the time has come to take ing at its diffraction limit could in theory telescope of diameter 50–100 m. Here the next step. produce images over five times sharper we present some highlights from this than the best images from today’s 6–10-m science case, ranging from direct ob- Several projects are under way around telescopes. These two effects together servations of Earth-like planets outside the world to design and construct have a profound effect on the scientific our own Solar System to the most dis- the next generation of ground-based, Ex- observations that can be made – from the tant objects in the Universe. tremely Large Telescopes (ELTs), which ability to resolve faint planets around will provide astronomers with the ability to other stars, to studying the most distant 1 Hook, I. M. (Ed.), 2005, “The Science Case for the address the next generation of scientific object in the Universe. European Extremely Large Telescope: The next step questions. Initial studies in the United in mankind’s quest for the Universe”. Printed copies States and Canada are concentrating on Some examples are given below of the and CDs are available on request from Suzanne potential designs in the 20–30-m range, potential scientific breakthroughs achiev- Howard ([email protected]). PDF files can be downloaded from http://www.astro-opticon.org/ such as the proposed Giant Magellan able with the vast improvement in sen- networking/elt.html Telescope (GMT) and Thirty Meter Tele- sitivity and precision allowed by the next

2 The Messenger 121 – September 2005 step in technological capabilities, focus- Table 1: Highlight science cases for a 50–100-m Extremely Large Telescope. ing on the science case for a 50–100-m telescope, which is being developed in Are there Terrestrial planets orbiting Are we alone? Direct detection of earth-like planets in extra-solar Europe. Additionally, as we have seen other stars? systems and a first search for bio-markers (e.g water and oxygen) in the past, each new generation of facili- becomes feasible. ties has advanced science by discover- How typical is our Solar System? What Direct study of planetary systems during their formation from proto- are the planetary environments around planetary disks will become possible for many nearby very young ing the new and unexpected. Therefore it other stars? stars. In mature planetary systems, detailed spectroscopic analysis is likely that the major scientific impact of Jupiter-like planets, determining their composition and atmos- of these new telescopes will be discover- pheres, will be feasible. Imaging of the outer planets and asteroids in ies beyond those we can predict today. our Solar System will complement space missions. When did galaxies form their stars? When and where did the stars now in galaxies form? Precision studies of individual stars determine ages and the distribution of the chemical elements, keys to understanding galaxy assembly and evo- Are we alone? lution. Extension of such analyses to a representative section of Planets beyond our Solar System the Universe is the next great challenge in understanding galaxies. How many supermassive black holes Do all galaxies host monsters? Why are supermassive black holes in In 1995 the first planet around a normal exist? the nuclei of galaxies apparently related to the whole galaxy? When and how do they form and evolve? Extreme resolution and sensitivity star other than the Sun was detected, are needed to extend studies to normal and low-mass galaxies to by the Swiss astronomers Mayor and address these key puzzles. Queloz, using a small French telescope When and where did the stars and the Can we meet the grand challenge, to trace star formation back to with sophisticated instrumentation. The chemical elements form? the very first star ever formed? By discovering and analysing distant rate of announcement of new discov- galaxies, gas clouds, and supernovae, the history of star formation, and the creation history of the chemical elements can be quantified. eries of extra-solar planets currently ex- What were the first objects? Were stars the first objects to form? Were the first stars the source ceeds several tens per year, with dis- of the ultraviolet photons which re-ionised the Universe some coveries dominated by indirect methods: 200 million years after the Big Bang, and made it transparent? These either the motion of the parent star in- objects may be visible through their supernovae, or their ionisa- duced by the gravitational pull of the plan- tion zones. et, or the light-loss resulting as the planet How many types of matter exist? What Most matter is transparent, and is detectable only through its gra- is dark matter? Where is it? vitational effect on moving things. By mapping the detailed transits in front of its star, as seen by growth and kinematics of galaxies out to high redshifts, we can us. First claims of direct imaging of planets observe dark-matter structures in the process of formation. have already been made using 8–10-m What is dark energy? Does it evolve? Direct mapping of space-time, using the most distant possible trac- telescopes (see Figure 2): it is only a mat- How many types are there? ers, is the key to defining the dominant form of energy in the Uni- ter of time until several reliable detections verse. This is arguably the biggest single question facing physical science. are available. Quantitative studies will Extending the age of discovery In the last decades astronomy has revolutionised our knowledge of become possible with advanced adaptive the Universe, of its contents, and the nature of existence. The next optics, using coronographic techniques to big step is likely to be remembered for discovering the unimagined suppress the glare from the planet’s new. parent star. Studies of Earth-like planets, especially via spectroscopy, will however remain impossible.

Extremely Large Telescopes offer spectacular advances in studying planetary systems. In addition to the improved collecting area, needed for observing such Figure 2: Infrared image obtained with 2MASSWJ1207334-393254 faint objects as the smaller extra-solar the NACO adaptive optics facility on the VLT of the young (~ 10 Myr) brown planets, the improved resolution allows dwarf 2M1207 (centre) in the nearby cleaner separation of a planet from TW Hydrae association (Chauvin et al. the image of its star. As a result, one of 2004). The fainter object seen near it the most exciting new opportunities at an angular distance of 778 milliarc- sec has recently been confirmed to be for Extremely Large Telescopes is the abil- gravitationally associated with the ity directly to detect and to study large brown dwarf. Models suggest that it is samples of planets in other solar systems. a giant exoplanet with a mass about five times that of Jupiter. The source is very young, is still liberating consider- Planets of course come in a wide range able energy as it contracts and cools, of types, sizes and distances from their and probably formed in a way unlike parent stars. What sort of planets can be that of planets in our Solar System. An 778 mas 55 AU at 70 pc studied with different types of telescope, ELT is essential to image fainter planets N like our Earth, particularly as they are and how many different planetary systems likely to be closer to their parent stars. might one be able to detect? Simula- E

The Messenger 121 – September 2005 3 Hook I. et al., Science with Extremely Large Telescopes

Figure 3: A simulated time-series image of a solar- system analogue, containing a Jupiter-like and an Earth-like planet at a distance of 10 pc. The system has been “observed” at number of epochs as the planets go around in the 15-degree obliquity orbits to illustrate the phase effect. Each epoch is represented by a 100-ksec exposure in the V-band with the OWL 100-m telescope, based on adaptive-optics simulations. The PSF of the central star has been subtracted from the image. (From Hainaut, Rahoui, & Gilmozzi 2005.) tions of observations of extra-solar planets show that a 30-m telescope at a “standard” site, equipped with suitably sophisticated adaptive optics instrumentation, should be capable of studying Jupiter-like gas giant planets out to several tens of light years, while only a much larger, 100-m-class, telescope would be capable of detecting and studying a sample of Earth-like planets – the key here 0.1 arcsec is the extremely high spatial resolution needed to observe an object that is about 10 billion times fainter than, and very close to its parent star. Earth, for example, would appear only 0.1ǥ from the sun strumentation which could detect Earth- ated by on going planet formation around if the Solar System were observed from like planets would with ease detect larger young stars. Current models, as yet a distance of 10 parsecs (~ 30 light years): planets, and planets with larger separa- untested by direct observations, suggest see the simulation in Figure 3. tion from their star. Imaging of entire plan- that planets form from condensations in a etary systems will become possible. dusty disc encircling a young star, and The habitable zone is the narrow region in Such data will define the outcome of the subsequently create circular gaps at dis- a planetary system where water exists formation of planetary systems, by dis- crete positions in the disc; Figure 4 shows in liquid form: this is a prerequisite for life covering and defining the types of sys- a simulation of this process. A telescope as we know it. Not all stars have plan- tems which form and survive. Basic ques- with sufficient resolving power and a coro- ets, and perhaps only a very few will have tions which remain unanswered to date nagraph to suppress light from the central planets in the habitable zone, so the larg- include which stars have which types of young star will be able to detect these est possible sample has to be surveyed planets, what conditions are required to planetary birthplaces, even at the inner if we are to be confident of identifying a form the various types of planet, what are disc locations where habitable planets true Earth-twin. The number of stars that the special properties, if any, of the parent should form. can be studied is approximately propor- stars and are there planets around rare tional to the spatial resolution to the cube types of stars (e.g. white dwarfs, very old A sub-millimetre detection capability on a (i.e. to D3, where D is the telescope halo stars: planets near neutron stars are suitably large telescope would even per- diameter). A 100-m telescope can in prin- already known). mit the mapping of the colder, outer ciple detect an Earth-like planet around a regions of protoplanetary systems out to solar-type star out to a distance of By repeated imaging, planets will be fol- their Kuiper Belts, where the debris of 100 light years. This distance limit means lowed around their orbits. Variations planetary formation is believed to accu- that there are about 1000 candidate in their apparent brightness during this mulate and survive. Sun-like stars to be observed. The corre- process then can be used to determine sponding numbers are about 200 stars many properties. For example, their for a 50-m telescope and 30 stars for a reflectivities (albedo) determine their sur- 30-m telescope. face temperatures. For larger planets, rings like those around Saturn, and the The large telescope collecting area, which presence of moons may be inferred is the key to achieving the challenging indirectly from the small deviations they goal of detection of an Earth-like planet produce in brightness, position of in a habitable zone, will automatically the planet and its velocity over time. allow substantial extra analysis, beyond ‘just’ detection: it will characterise planetary surfaces and atmospheres. Worlds in formation The search for biomarkers in the planet atmosphere has the potential to discover At least as important as determining the life beyond our Solar System. diversity of mature planetary systems is understanding the formation and early evolution processes. Is planet formation Massive planets ubiquitous but survival unlikely? Or vice- versa? How long does planet formation A limitation in studies of our own Solar take? How is it terminated? What hap- Figure 4: Simulation showing four stages in the for- System is that we have only one example: pens to a planet after it forms? All these, mation of gas giant planets via fragmentation of protoplanetary discs (from Mayer et al. 2004). As the plan- is what we see typical? unique? tran- and many related, questions require ets form, gaps are carved in the disc. An ELT has the sient? It is clear that a telescope and in- detection of the observable effects gener- potential to detect such gaps.

4 The Messenger 121 – September 2005 Solar System astronomy Figure 5: Changes in the surface of Io observed by the Galileo An Extremely Large Telescope provides spacecraft. The images a natural and valuable complement to were taken on April 4 dedicated spacecraft. It would be capable and September 17 1997. of assembling a unique atlas of the (Credit NASA /JPL). Ground-based ELTs will surfaces of hundreds of solar system ob- allow repeated imaging jects. Of unique value will be an Extremely and monitoring of such Large Telescope’s ability to make re- events. peated highly-resolved imaging and spectroscopic observations of planets and moons with evolving surfaces and atmospheres. Detailed and continuing observations of this kind cannot otherwise be obtained except by dedicated (single-target) orbiters, none of which have yet been sent to the outer Solar System. Figure 5 redshifts up to ten in the case of a 100-m Figure 6 (below): Hubble diagram, normalised to a shows an image of Jupiter’s moon Io telescope (see Figure 6) and possibly to cosmological model for an empty Universe, for supernovae out to redshift 20 (from Della Valle et al. 2005). taken during a fly-by of the Jupiter orbiter redshift 20 for supernovae from the very Pink dots are simulated Type Ia SNe, black dots Galileo: a 100-m telescope for example first (population III) stars. Redshift ten cor- Type II (+Ib/c), blue and green dots are Ia SNe actually would have a diffraction-limited resolution responds to direct observation back to discovered by groundbased telescopes (Perlmutter et of about 8 km (at a wavelength of 1µm) 500 million years after the Big Bang, bare- al. 1998, 1999; Riess et al. 1998; Knop et al. 2003, Tonry et al. 2003) and from HST (Riess et al. 2004). at the distance of Io, allowing detailed ly 3 per cent of the present age of the The SNe have been distributed around the track surface maps to be made and changes to Universe. The frequency of supernovae at ΩM = 0.3, ΩΛ = 0.7 after taking into account the intrin- be monitored (such as the volcanic activi- different times in the history of the Uni- sic dispersion of the peak of the luminosity of Type Ia ty shown in Figure 5). Thermal-infrared verse is directly related to the number of and II SN populations, while the photometric errors have been derived from the S/N ratio that has been images at these resolutions have never stars that formed at that particular cosmic computed for each simulated observation, assuming been secured. epoch. Measuring the rate of supernova a 100-m telescope. Red dots represent SNe from explosions across the Universe can there- Pop III star population. A 100-m ELT could generate Such a systematic series of imaging and fore tell us when stars formed and at what such a sample of supernovae in about 130 nights of observing, including crucial measurements of spec- spectroscopic observations would also rate. Simulations suggest that a 100-m troscopic redshifts and determination of the superno- allow us to follow the seasonal and long- telescope would require about 130 nights va types. term variability of Titan’s dense haze lay- both to discover ~ 400 supernovae (using ers, allow studies of the structures generated by the gas geysers on Triton and permit the monitoring of the evolution of Ωm = 0 ΩΛ = 1 the atmosphere of Pluto as it recedes from the sun. 1

When and where did the stars form? Ωm = 0 ΩΛ = 0 0 When did the stars form? This basic = 0.3 = 0.7 question is a key puzzle in astronomy and Ωm ΩΛ is only partly answered: young stars are being born today in our and other galax- -1 ∆ ies, but at a very low rate. Most stars m were formed long ago. But when were the stars that make up the giant elliptical -2 galaxies and the central bulges of spirals like our own Milky Way formed? To answer this we can make use of the fact Ωm = 1 ΩΛ = 0 that massive stars die young. Indeed -3 many explode only a few million years after their birth, in spectacular supernovae explosions, whose flash can outshine whole galaxies. With an Extremely Large -4 Telescope, such supernovae could be 0 5 10 1520 seen to vast distances, corresponding to z

The Messenger 121 – September 2005 5 Hook I. et al., Science with Extremely Large Telescopes

Figure 7: A predicted distribution of stars as a function of magnitude (vertical axis), colour (horizontal axis) and age, for a plausible galaxy model (from Aparicio & Gallart 2004). The colour coding represents stars in different age intervals, with units in billions of years. A 100-m-class ELT would have the resolving power and collecting area needed to place individual stars on such a diagram, and hence measure the age of the stellar populations, in galaxies as distant as the Virgo cluster. near-infrared imaging in the J-, H- and -8 t ≤ 0.1 K-bands) and to carry out spectroscopy 0.1 < t ≤ 0.4 0.4 < t ≤ 1.0 to confirm their nature, redshift and 1.0 < t ≤ 3.0 properties. Such a sample will provide a -6 BL 3.0 < t ≤ 6.0 reliable measure of the star-forming his- 6.0 < t ≤ 10.0 tory of the Universe back to a time when 13.0 < t ≤ 10.0 the Universe was a few per cent of its -4 present age. Labels indicate different stellar evolutionary

I HB phases:

M -2 AGB BL – Blue Loop When did the stars assemble into today’s HB – Horizontal Branch galaxies? RC RC – Red Clump 0 RGB – Red Giant Branch AGB – Asymptotic giant How did the galaxies that we observe RGB branch around us come to be formed? This MS – Main Sequence remains one of the outstanding questions 2 MS in modern astronomy. The current best model suggests that a hierarchical sequence of mergers of smaller component 4 galaxies built up most of the galaxies we -1 0123 see today. Indeed, recent studies of (V–I) our own Milky Way galaxy have revealed a few small galaxies currently merging into indeed, of the components from which) In addition, the bulk motions of gas and the Milky Way, while similar behaviour is the target galaxies were assembled, and stars inside galaxy could be determined, apparent in our neighbour the Andromeda the role of dark matter in this process. thus allowing one to map the dark matter galaxy M31. Detailed analysis of merg- content of individual galaxies at a range of er events gives clues as to the timing of redshifts, corresponding to epochs when the main mergers in a galaxy’s history and The physics of galaxy formation the galaxies were in the process of as- through this, the role of the mysterious sembly. Then, measuring the kinematics dark matter, which must play an important To understand the creation and evolution of their satellite objects, both internal and part in galaxy formation through its domi- of galaxies in general we must address relative to their more massive partners, nant gravitational effect. what is one of the major goals of future we can estimate the amount of and infer astrophysics: to map the distribution and the distribution of the mass present in the Up until now these studies have been lim- growth of both the baryonic (normal galaxy’s halo, which is one of the few ited to our own Galaxy and its nearest matter) and dark matter components of ways we have of detecting and examining neighbours. But do all galaxy types have galaxies at moderate to high redshift the dark matter and its distribution. similar merger histories? How important (z = 1–5), a key epoch for galaxy forma- is environment? To study a representative tion. Although individual stars cannot This will provide astronomers with a de- section of the Universe requires reaching be resolved at these cosmological dis- tailed evolutionary history of the clump- at least the nearest large galaxy clus- tances, a 50-m to 100-m Extremely Large ing of dark matter (Figure 8). We will “see” ters which contain large elliptical galaxies. Telescope will not only resolve the dis- galaxy formation in all its glory from for- This means observing galaxies in the tant galaxies into their luminous compo- mation to maturity, and so directly test our Virgo or Fornax clusters at distances of 16 nents, but will be able to characterise understanding of the basic evolutionary or 20 mega-parsecs respectively. Initial these individual components. processes in the Universe. feasibility studies look very promising – simulations show that a 100-m-class tele- Using techniques such as integral-field scope should be able to resolve individ- spectroscopy, in which spectra are ob- Supermassive black holes ual stars in galaxies in the Virgo cluster, tained at thousands of locations across a and obtain sufficiently accurate photome- (proto-) galaxy simultaneously, it will be The centres of most, perhaps all, galaxies try to determine their ages and composi- possible to determine the relative star for- harbour supermassive black holes. These tion, even for the oldest, hence faintest, mation rate, the mass of stars and the exotic objects are usually discovered indi- unevolved stars. Spectroscopic observa- chemical composition at these different rectly, as extreme radio- or X-ray-lumi- tions of the brighter stars will also be pos- locations within each galaxy. This will nous sources, quasars and Active Galac- sible, allowing measurements of the kine- shed light on the “feedback” mechanisms tic Nuclei. Direct studies, critical for matic motion of the stars and accurate believed to affect the formation of galax- reliable mass determination, and essential determination of their chemical composi- ies, such as the effects of a newly-formed when the hole is not active, are possi- tion. From these a detailed picture will be active galaxy nucleus, or supernova ex- ble only when precision studies of the derived of the process by which (and, plosions, on surrounding star formation. very local region of the galactic nucleus are feasible: only (relatively) close to a

6 The Messenger 121 – September 2005 black hole is the gravity of the whole galaxy dominated by the mass of the black hole, so that the black hole’s presence can be deduced. The methodology has been proven by observations at ESO over many years proving the existence 6 of a massive (~ 3 × 10 Mी) black hole in the core of the Milky Way galaxy. Direct measurements of the speed at which stars and gas clouds are orbiting the cen- z = 4.71 z = 4.00 z = 2.64 tre of a galaxy are required. The closer to the centre these can be measured, the more reliable is the evidence for, and the determination of the mass of, the black hole.

For reasons which are not understood, the evolution and mass of the supermassive black holes is apparently very closely related to the properties of the very much larger host galaxy. Understanding z = 2.08 z = 1.56 z = 1.35 this, and determining if it is indeed ubiquitous, would be the first clue relating the nuclei of galaxies to their major parts, and the first link between the exotic and the typical in galaxies. How do the black holes first form? How do they grow, and at what rate? Are growing black holes always active? How does a central black hole “know” the properties of the larger galaxy in which it resides? Does every galaxy have a massive black hole? z = 0.90 z = 0.38 z = 0.00

All these questions require for progress detailed study of the masses and ubiquity early Universe an opaque gas of hydrogen Figure 8: Simulations showing Dark Matter particles of central black holes. This requires the and helium. Some time later, the first ob- within a cube of 320 physical kpc on a side, shown at various redshifts and projected so that the luminous highest possible spatial resolution and jects heated the hydrogen and helium, galaxy at z = 0 is seen edge-on (from Abadi et al. faint-object spectroscopy, attainable only making it (again) transparent – the “era of 2003). The bottom right panel zooms into the inner- with an extremely large telescope. For (re-)ionisation’’. A key goal of astrophysics most 40 kpc of the system. Each particle is coloured example, Figure 9 shows that a 100 m is to understand how and when the first according to the logarithm of the local dark matter density using a palette that runs from red to blue: red telescope working at its diffraction limit luminous objects in the universe formed and blue correspond to ρdm greater than and less 10 –3 can in principle resolve the sphere of influ- from the primordial gas, what they were, than about 10 Mी kpc respectively. An ELT has the 9 potential to observe such galaxy haloes in the pro- ence of a supermassive (10 Mी) black and how they contributed to ionising and hole at all redshifts across the Universe enriching the gas with heavy elements. cess of formation: observations of the motion of the central galaxy and its satellites will provide a mea- (provided they exist of course!) and even surement of the distribution of dark matter in the ex- detect the influence of a modest 100 Mी Tantalising questions about the re-ionisa- tended galaxy halo. black hole in the local Universe, out to tion history of the universe are raised by about 1 Mpc from us. It will then be possi- recent results. Those from the Wilkinson- ble to carry out a systematic census of MAP Cosmic Microwave Background sat- pletely all radiation bluer than the Lyman α black holes as a function of cosmic epoch ellite probe, when combined with ground- recombination line of HI (Figure 10). What and begin to understand their formation in based surveys of the large-scale structure is the solution to this apparent quanda- relation to the galaxies around them. of the Universe today, suggest that the ry? It may be that there were two re-ioni- gas was re-ionised by about 180 million sation epochs, an earlier caused by the years after the Big Bang (redshift ~ 17) first generation of massive stars, followed The ionisation of the Universe while observations of the highest redshift by cooling, and then one later by the quasars at about 700 million years (red- first quasars and galaxies. Alternatively, a The early Universe was hot (ionised) and shift ~ 6) demonstrate that enough of the slower, highly inhomogeneous re-ioni- transparent. With time, the gas cooled. intergalactic medium remained un-ion- sation process may have occurred over The aftermath of the Big Bang left the ised at that time to absorb almost com- the period between the two epochs.

The Messenger 121 – September 2005 7 Hook I. et al., Science with Extremely Large Telescopes

Figure 9: Left: Artist’s conception of an AGN with the Supermassive black holes black hole surrounded by accreting material and -1.0 ejecting jet at relativistic velocities. Right: The impact 100-m ELT of a 100-m-class telescope on studies of interme- 30-m ELT -1.5 9 10 Mी diate and massive black holes would be considerable. 8 10 Mी 7 Shown here are the distances to which the sphere 10 Mी 6 ] 10 Mी of influence can be resolved (for comparison, the res- c -2.0 e olution of a 30-m telescope is also shown). With a s c

9 r

100-m ELT we be able to detect 10 M black holes a ी [

) -2.5

at all redshifts (where they exist). Here we assume H –1 –1 B a cosmology of H = 70 km s Mpc , Ω = 0.3 and R 0 M ( = 0.7. The point spread function is given by g ΩΛ o

l -3.0 1.22 λ/D, where D is 30 m or 100 m and λ = 1 µm. (Figure credits: Left: GLAST/NASA, Courtesy Aurore Simonnet, Sonoma State University, Right: -3.5 M. Hughes.) -4.0 1 234 56 1+z

Figure 10: Spectra of quasars of increasing redshift illustrating the increase in absorption due to intervening neutral gas with increasing redshift. At the highest redshifts these show a “Gunn-Peterson” absorption trough – the complete absorption of light at wavelengths shortward of the Lyman α line of atomic hydrogen – implying that the re-ionisation epoch which began at redshift ~ 20 must have continued until redshift ~ 6. An ELT’s supreme sensitivity to point sources (such as quasars, gamma ray bursts and supernovae) will allow observations of the ionisation state of the Universe to very high redshift, possibly all the way back to when the re-ionisation process began. (Figure shows observations by W. Sargent & M. Rauch; Tae-Sun Kim; M. Pettini. Compilation by R. Carswell.)

These models, together with other more complex possibilities, could be tested if we can observe the ionisation state of the high-redshift Universe directly: this is feasible, through analysis of the absorption features produced in the spectra of suitably-luminous very distant “background” objects. There are a few popu- er redshift. Although the epoch of first The first galaxies lations of sources that could be observed quasar formation remains an open ques- at such very high redshift with an ELT. tion, the quasars being found at redshifts The first galaxies, being the places of for- The short-lived gamma-ray bursts are around 6 are (presumably!) powered by mation of the first stars (a prediction well extremely bright for a short time, so much supermassive black holes, so we infer worth verifying!) compete with the first so that they should be detectable up to that intermediate-mass black holes (cor- quasars for the re-ionisation of the gas in redshift ~ 15–20. Supernova explosions responding to quasars of intermediate the early Universe. Candidate star-forming of the first stars to form, though not luminosity) must have existed at earlier galaxies out to redshift about 6 have yet detected, would probably be fainter epochs, up to at least redshifts of about already been discovered and a few have than this, but could still be used to probe 10. Probing the physics of the gas in the been confirmed spectroscopically. Equiv- the state of the gas at redshifts up to 10. early Universe requires intermediate/high- alent objects are expected to exist out This population of “first supernovae” may resolution spectroscopy of these “back- to redshifts greater than 10 for several well disappear once the local heavy- ground” sources in the near infrared, the reasons. Firstly, the analyses of the fluctu- element enrichment becomes higher than natural domain of ground-based Extreme- ations in the Cosmic Microwave Back- 1/10000 of the solar value. Testing this ly Large Telescopes. Apart from the very ground indicate ionisation of the universe prediction will itself be a major challenge, rare extreme gamma-ray bursters (and/or at redshifts > 10, presumably by ultra- and discovery. bursts caught very early), which could be violet emission from the first objects. Sec- observed with a 30-m-class telescope, ondly, SPITZER satellite observations of Quasars are currently used as powerful spectroscopic observations of these faint the higest redshift galaxies known to date background sources, and will continue background objects can only be carried show evidence for old stellar populations to be useful in future, if they exist at high- out with telescopes of the 60–100-m class. – indicating that these galaxies formed

8 The Messenger 121 – September 2005 Figure 11: HST/ACS images of high-redshift (z ~ 5–6) galaxies from Bremer & Lehnert (2005) showing the small but resolved nature of the galaxies, with typical half-light radii of 0.1–0.2 arcsec (1–2 kpc). A 50 to 100-m ELT will not only measure detailed physical properties of such galaxies but will also be capable of finding and confirming (with spectroscopy) galaxies at significantly higher redshifts (10 and beyond), possibly including the first galaxies to form in the Universe. much earlier. Very high-redshift star-forming galaxies will probably be detectable in considerable numbers with future spacecraft (James Webb Space Telescope) and ground-based (ALMA) facilities. However a 100-m-class Extremely Large Telescope will be needed to provide the desired di- 5011 5225 5296 5307 5788 agnostics of the astrophysics of both the gaseous interstellar medium and the early stellar populations in these galaxies.

Furthermore, a sub-millimetre capability on an Extremely Large Telescope, if 2399 3250 3262 3968 4173 it were at a suitable site, would allow a large-scale survey (with mapping speed thousands of times faster than ALMA at 850 µm) that would detect the millions of dusty high-redshift galaxies which (probably) contribute the cosmic far-infrared and sub-mm background, resolved 443 712 1276 1392 2225 down to quite faint levels throughout the Universe. With redshift estimates from sub-mm flux ratios, such a survey would of the effects of dark energy are apparent gested by modern versions of quantum yield a treasure-trove of information at relatively low redshifts (less than about field theories. The need for these obser- on large-scale structure from very early z = 1), although equivalent studies at high vations is critical and the implications for epochs to the recent past. redshift, when feasible, may well have their all of physics and cosmology are vast. own surprises in store. Furthermore, ELTs offer the intriguing pos- Dark energy and fundamental physics An Extremely Large Telescope can deter- sibility of observing the expansion of mine the expansion history of the Uni- the Universe directly – by observing the The recent discovery of the accelerating verse using several different and comple- minute increase in redshift of absorp- expansion of the Universe has led to an mentary astrophysical objects, thus tion lines in quasar spectra over a period urgent need to understand the nature of decreasing any dependency on possibly of about 10 years it will be possible to the mysterious “dark energy” which is unknown systematic effects. The well- watch the Universe expanding in “real driving this expansion. The dark energy is understood primary distance calibrators, time”! Such detailed and direct measure- believed to account for about 70 per cent pulsating Cepheid stars, globular clusters, ments will provide an important test of of the energy budget of the Universe planetary nebulae and novae, could all in cosmological models and also allow tests (Figure 12, see next page) and yet its principle be observed to cosmological for the constancy of fundamental parame- nature is completely unknown. One po- distances where the effect of dark energy ters such as the fine structure constant. tential candidate is the vacuum energy is dominant in the Universe. The exquisite implied by the “cosmological constant” sensitivity to point sources of an Extreme- Cosmological observations have now term in Einstein’s field equations (whose ly Large Telescope with appropriate adap- become the only way to characterise sev- solutions represent global pictures of tive optics capability, combined with its eral of the most promising unexplored the Universe). However measurements of impressive collecting area, will allow it to sectors beyond the Standard Model the effects of dark energy on cosmo- detect Type Ia supernovae to redshift of particle physics. The discovery and de- logical scales constrain its contribution to of about 4, and Type II supernovae (which scription of dark energy is possible only be many orders of magnitude smaller can also be used as distance indicators with cosmological-scale observations: no than the vacuum energy scale predicted via the expanding photosphere method) small-scale effects are yet known. Howev- by particle physics theories. possibly all the way to redshifts of about er, dark energy and dark matter must ten (see Figure 6). be part of the process towards under- The direct measurement of the dynamical standing the next generation of theory in expansion history of the Universe via By mapping the geometry of the Universe Physics: they are related to super-sym- Type Ia supernovae has shown that the on the largest scales and accurately metric particles, string theory, theories of dark energy exerts a negative pressure determining any variations of the strength gravity and quantum gravity, theories and hence accelerates the universal of dark energy with time, astronomers of higher dimensions, and the constan- expansion. Direct analysis of the expan- can answer the fundamental question of cies of the fundamental constants. An sion rates of the Universe across space- whether dark energy corresponds Extremely Large Telescope is the next big time is needed to investigate this remark- to Einstein’s cosmological constant or step in direct observation of the nature able form of energy. Intriguingly, most to some “quintessence field” as sug- of the Universe.

The Messenger 121 – September 2005 9 Hook I. et al., Science with Extremely Large Telescopes

Figure 12: Our current understanding of the mass- energy content of the Universe. All “normal” matter is a minor contribution of only about 4 %. Dark matter, of unknown nature dominates mass. Dark energy, of unknown identities, dominates the Universe. What is it? ELTs can tackle this question by measuring the expansion history of the Universe using a range of independent techniques. Why an ELT now?

The relatively large apertures which are affordable and technically feasible Dark energy for groundbased telescopes means that 73 % these facilities are the natural means to provide maximal light-gathering power. Natural complementarity exists between these and orbiting observatories which, Atoms although considerably more expensive for 4 % the same size of telescope, benefit from being clear of the thermal background Cold dark matter and the seeing effects of the Earth’s at- 23% mosphere.

For example, routine images from the Hubble Space Telescope’s Advanced sources which will demand further study WWW sites for further information: Camera for Surveys reveal objects which at other wavelengths. For example OPTICON European ELT science case are so faint the largest existing teles- the Low-Frequency Array (LOFAR), due work: http://www.astro-opticon.org/ copes are unable to acquire their spectra. for completion in 2008, will operate at networking/elt.html Without spectroscopic information we long radio wavelengths, and a more ambi- Euro-50 telescope web site: can learn only a limited amount about the tious project, the Square Kilometer Array http://www.astro.lu.se/~torben/euro50/ basic nature and properties of an astro- is being proposed to follow as the next- OWL telescope web site: physical object. The advent of the James generation radio facility. In the sub-mm http://www.eso.org/projects/owl/ Webb Space Telescope, currently sched- bands the Atacama Large Millimeter Array uled for launch in 2012, will increase this (ALMA), an interferometer currently in References imbalance. Until the astronomical com- the initial stages of construction and a key munity acquires complementary ground- element of ESO’s scientific strategy, Abadi M. G., Navarro J. F., Steinmetz M., Eke V. R. based facilities which are much larger will provide very high sensitivity and spa- 2003, ApJ 591, 499 than those available at present, the major- tial resolution beyond the limits of cur- Andersen T., Ardeberg A., Owner-Petersen M. 2003, “Euro50, A 50-m Adaptive Optics Telescope”, ity of future discoveries will be beyond rent ground-based telescopes. ALMA is Lund Observatory our spectroscopic reach and detailed un- due to be fully operational by 2012 and Andersen T., Ardeberg A., Riewaldt H., Quinlan N., derstanding. This is a major reason will cover a very wide range of science, Lastiwka M., McNamara K., Wang X., Enmark A., why astronomers are urgently seeking to detecting both thermal continuum emis- Owner-Petersen M., Shearer A., Fan C., Moraru D. 2004, SPIE 5489, 407 begin construction of the first ground- sion from dust and line emission in Aparicio A. & Gallart C. 2004, AJ 128, 1465 based Extremely Large Telescopes. objects from the nearest star-forming re- Bremer M. & Lehnert M. 2005b, in proc “The Evolu- gions to luminous galaxies at very high tion of Starbursts” AIP Proc 331. Heraeus Seminar: Space observatories which are designed redshift. Groundbased Extremely Large The Evolution of Starbursts Eds. Huettemeister, Manthey, Aalto, Bomans for observations at wavelengths inacces- Telescopes will be ideally matched to pro- Chauvin G., Lagrange A.-M., Dumas C., Zuckerman sible from the ground (because of absorp- vide imaging and spectroscopic follow-up B., Mouillet D., Song I., Beuzit J.-L., Lowrance P. tion by the Earth’s atmosphere), such of these sources at optical to mid-infra- 2004, A&A 425, L29 as the flagship X-ray facilities XMM-New- red wavelengths, with matched angular Della Valle M., Gilmozzi R., Panagia N., Bergeron J., Madau P., Spyromilio J., Dierickx P. 2005, in proton and Chandra, regularly discover resolution. ceedings of the Berlin-04 meeting “Exploring the sources which are too faint in the wave- Cosmic Frontier”, Springer-Verlag series “ESO length range readily accessible to the Astrophysics Symposia”, ed. A. Lobanov, in press. ground, the optical and near infrared, to Science Case Development See also astro-ph/0504103 Dierickx P., Brunetto E., Comeron F., Gilmozzi R., be detected or investigated by existing Gonte F., Koch F., le Louarn M., Monnet, G., telescopes. Planned next-generation mis- This summary is based on a full science Spyromilio J., Surdej I., Verinaud C., Yaitskova N. sions will further increase the need for case document developed at a series 2004, SPIE 5489, 391 a major enhancement in the performance of meetings over four years involving over Gilmozzi R. 2004, SPIE 5489, 1 Hainaut O., Rahoui F., Gilmozzi R., 2005, in proceed- of our large optical/near infrared tele- 100 astronomers. The work is sponsored ings of the Berlin-04 meeting “Exploring the scopes if the new phenomena which they by the EC network OPTICON, and main- Cosmic Frontier”, Springer-Verlag series “ESO reveal are to be understood. tained as part of the European Extremely Astrophysics Symposia”, ed. A. Lobanov, in press Large Telescope Design Study, funded in Knop R. et al. 2003, ApJ 598, 102 Mayer L., Quinn T., Wadsley J., Stadel J. 2004, ApJ New radio and sub-millimetre astronomy part by the EC FP6 programme, by ESO, 609, 1045 groundbased facilities are being built and by many European national agencies Perlmutter S. et al. 1998, Nature 391, 51 that will also naturally complement an Ex- and organisations. Perlmutter S. et al. 1999, ApJ 517, 565 tremely Large Telescope’s optical and Riess A. et al. 1998, 116, 1009 Riess A. et al 2004, ApJ 607, 665 infrared capabilities, and will discover Tonry J. et al. 2003, ApJ 594, 1

10 The Messenger 121 – September 2005 Reports from Observers

Deep Impact at ESO Telescopes

Hans-Ullrich Käufl1 This article is a first summary of the ob- of the short-period comets, while the Nancy Ageorges1 servations done with ESO telescopes Oort Cloud contains comets originating Stefano Bagnulo1 and instrumentation in the context of in general from the region of birth of the Luis Barrera 2 NASA’s Deep Impact (DI) space mission. major planets in the Solar System. Hermann Böhnhardt 3 The ESO observers* were part of an Tanyu Bonev 4 extremely active, communicative and Gravitational interaction with the outer Olivier Hainaut1 thus successful worldwide network of planets and the immediate and even more Emmanuel Jehin1 observers. Through this network all distant neighbourhood of the Sun in Florian Kerber1 information was freely exchanged and the Milky Way (passing stars, molecular Gaspare LoCurto1 highlights are reported here as well. clouds, galactic centre) has moved and Jean Manfroid 5 stored these cometary nuclei into the Oort Olivier Marco1 Cloud, now the repository of non-periodic Eric Pantin6 Comets and the formation of the comets. It is the same process, gravita- Emanuela Pompei1 Planetary System tional interaction with stars and molecular Ivo Saviane1 clouds passing our Solar System, which Fernando Selman1 The most important scientific rationale for is responsible for injecting comet nuclei Chris Sterken7 studying comets is to obtain informa- from their storage place back into the in- Heike Rauer 8 tion on their origin, on their relationship ner Solar System where they can be ob- Gian Paolo Tozzi 9 with interstellar and interplanetary materi- served from Earth. Comets then become Michael Weiler 8 al, and on implications for the formation sometimes spectacular objects, since of the Solar System. The knowledge close to the Sun, the frozen volatiles subli- about comets had been synthesized in mate, which creates the dust and gas 1 ESO the 1950s by Fred Whipple into the comae. Coma is the Latin word for “hair” 2 Universidad Metropolitana de Ciencias “Dirty Snowball” model for cometary and thus, comets have been referred to de la Educacíon, Santiago de Chile, nuclei. Today comets are referred to as as “hairy stars” by our ancestors. Chile “icy dirt balls” of the solar system be- 3 Max-Planck-Institut für Sonnen- cause this is a better reflection of their Since comets stayed inactive most of systemforschung, Katlenburg-Lindau, constitution of frozen volatiles and dust. their lifetime in the cold environment of Germany Comets are known to arrive in the inner the outer Solar System, they are believed 4 Institute of Astronomy, Sofia, Bulgaria planetary system coming from two main to be primordial, i.e. representing in a 5 Université de Liège, Belgium reservoirs: the Oort Cloud at several close to original form an important popu- 6 CEA, Saclay, France 1000–10 000 AU distance from the Sun, lation of minor bodies that agglomerated 7 Vrije Universiteit Brussel, Belgium and the Edgeworth-Kuiper Belt at in the protoplanetary disc from inter- 8 Deutsches Zentrum für Luft und 30–50 AU from the Sun. The latter is con- stellar dust some 4.6 billion years ago. Raumfahrt, Germany sidered to be also the birthplace of most Comets can thus be considered as fossil 9 Istituto Nazionale di Astrofisica (INAF) – records from the formation of our Solar System. Of course, any fossil on Earth Osservatorio di Arcetri, Italy * The ESO observations were the result of a worldwide scientific cooperation involving the following has been subject of some type of “weath- colleagues: Michael A’Hearn (University of Maryland, ering”. Similarly cometary nuclei have not USA), Claude Arpigny (Université de Liége, Belgium), survived 4.5 billion years in the Solar Sys- Anita Cochran (McDonald Observatory USA), tem without any changes. Their upper Catherine Delahodde (University of Florida, USA), Yanga Fernandez (University of Central Florida, USA), surface layers of a few metres thickness Damien Hutsemekers (Université de Liège, Belgium), experience evolutionary modifications Hideyo Kawakita (Gunma Astronomical Observatory, due to cometary activity, space weather- Japan), Jörg Knollenberg (Deutsches Zentrum für ing and collisions with other minor bod- Luft und Raumfahrt, Germany), Ludmilla Kolokolova (University of Maryland, USA), Mike Kretlow ies. Hence it is not surprising that comets (Max-Planck-Institut für Sonnensystemforschung, have very high priority on the target lists Germany), Michael Küppers (Max-Planck-Institut für of interplanetary missions of the national Sonnensystemforschung, Germany), Ekkehard Kührt and international space agencies: trig- (Deutsches Zentrumfür Luft und Raumfahrt, Germany), Luisa Lara (Instituto de Astrofísica de gered by Halley’s comet’s encounter of a Canarias, Spain), Javier Licandro (Instituto de fleet of five spacecraft in 1986, four more Astrofísica de Andalucía, Spain), Casey Lisse (The comets were explored by man-made John Hopkins University/Applied Physics Laborato- scientific instrumentation in fly-by mis- ry, USA), Karen Meech (Universitiy of Hawaii, USA), Rita Schulz (ESTEC, the Netherlands), Gerhard sions up to the last year. At this point, the Schwehm (ESTEC, the Netherlands), Michael Sterzik exploration of comets with ground-based (ESO), Joachim A. Stüwe (Universiteit Leiden, the telescopes and fly-by spacecraft had Netherlands), Isabelle Surdej (Université de Liège, resulted in a cornucopia of many, some- Belgium), Diane Wooden (NASA Ames Research Center, USA) and Jean-Marc Zucconi (Besançon, times fairly sophisticated detailed obser- France). vations. The most important parameters

The Messenger 121 – September 2005 11 Reports from Observers Käufl H.-U. et al., Deep Impact at ESO Telescopes

of a solar-system body, density and thus mass and the tensile strength of surface and interior, however, were the subjects of theoretical conjectures, but remained basically undetermined. It was thus important to take the next logical step: 2005 has seen a new flavour of cometary exploration, Deep Impact, an active experiment with a cometary nucleus.

The Deep Impact mission

On 4 July 2005, NASA’s discovery mission Deep Impact (DI) encountered Comet 9P/Tempel 1, releasing a 370 kg copper probe at the comet (A’Hearn 2005). The probe was hit by the comet nucleus at a speed of 10.2 km/s and penetrated into the upper surface layers of the nucleus while the mother spacecraft flew by the nucleus at a distance of about 500 km observing the event with three on-board remote sensing experiments, a wide- and a narrow-field camera (visible wavelength range) and a near-infrared imaging spectrometer (1–5 micron). The target comet, 9P/Tempel 1, is a medium-bright, slowly rotating (41 h), medium-size (> 7.5 km diameter), low-albedo (8 %) short-period comet, most likely originating in the Edgeworth-Kuiper Belt. During the impact the kinetic energy released by the Figure 1: Comet 9P/Tempel 1 imaged 67 seconds impactor was 19 GigaJoule or 5 300 kWh after it obliterated Deep Impact’s impactor spacecraft. The image was taken by the high-resolution camera (this amount of energy is equivalent to on the mission’s fly-by spacecraft. The image reveals the biannual electricity consumption by topographic features, including ridges, scalloped the author in his apartment for which edges and possibly impact craters formed long ago. the local public utility company charges First light from the impact flash arrived on Earth at 05:52:03.3 UT. For ESO telescopes the comet had approximately 900 €. Or it is slightly more just set (see text). than the equivalent of an Airbus A380 Image credit: NASA/JPL-Caltech/UMD. airplane flying at cruise speed – pick the unit which is more familiar to you!). mission, the spacecraft could perform complementary means to guarantee the only a short monitoring campaign of the expected science return and the success Models describing the subsequent crater target peaking in an approximately of the mission. Hence, they formed an formation resulting from this experiment 800 sec long period around close en- integral part of the DI mission concept gave a wide range of predictions, from the counter, when the impact area was and have been coordinated world-wide by comet swallowing the impactor with vir- in direct view of the instruments on board a dedicated mission scientist (Karen tually no effects, to complete disruption of the fly-by spacecraft. Figure 1 shows Meech, University of Hawaii, see Meech the nucleus. The most likely models pre- an example of images taken by the fly-by 2005). Due to the limitations of man-made dicted a crater of football stadium size, an spacecraft. interplanetary spacecraft a short-period impact flash, an ejecta plume with a comet had to be picked for this experi- high probability that pristine material from ment. The comet should have a perihelion the inner “original” layers is released dur- Need for earth-based DI science not too far from our Earth’s orbit. The ing and after impact, when the Sun will encounter could only take place close to illuminate this newly formed active region Given the limited scope of the on-board a crossing point of the cometary orbit on the nucleus. Under lucky circum- instrumentation (described in Hampton, with the orbital plane of the Earth, the stances even a new long-lasting active 2005) and the short visibility of the impact Ecliptic. For Comet 9P/Tempel 1, one of region might have been created by area from the spacecraft, Earth-based the few comets fitting the set of con- the impact. Due to the fly-by nature of the observations were the most important straints, perihelion passage (July 5, 2005)

12 The Messenger 121 – September 2005 Figure 2: The participants of the ESO-Deep- Impact preparatory workshop in February 2004.

was very close to the descending node refer to Comet 73P/Schwassmann- critical event such as Deep Impact, this crossing (July 7, 2005). To have optimum Wachmann 3 (c.f. http://www.eso.org/ was, of course, an invaluable asset, espe- conditions for ground based follow-up, outreach/press-rel/pr-1996/pr-01-96.html). cially in Chilean winter! the event should take place during “dark In that sense it was considered advanta- time” (new moon July 6, 2005). These geous, that the comet became visible constraints set the date for the experi- in Chile 16 hours after impact. Given the The coordinated ESO DI campaign ment. The visibility of the immediate light-collecting power and instrumental impact event on Earth covered most of multiplexing capabilities, the ESO obser- For an optimum preparation of the cam- the Pacific Ocean region except for the vatories in Chile were considered critical paign, an impromptu weekend workshop west coast of South America. ESO’s sites for the ground-based observational was sponsored and organised at ESO role in the scientific follow-up was to coverage of the impact event. Moreover, in February 2004, to get the ESO commu- study and document the activity of Comet ESO is in the special position of having nity involved. Many of the participants had 9P/Tempel 1 until shortly before impact. its telescopes located on two different been involved in the July 1994 observing The comet set for Chile approximately mountain tops separated far enough geo- campaign for the collision between the two hours before impact. From the study graphically that they have different weath- fragments of Comet Shoemaker-Levy 9 of spontaneously broken-up comets er. Both sites by themselves are already with Jupiter (SL9, c.f. The Messenger 77, it was known, that the break-up related excellent astronomical sites, but in combi- 1994 or http://www.eso.org/outreach/ phenomena peak in brightness 12–24 nation it is highly unlikely that both obser- info-events/sl9/). In total five proposals hours after the event. For an example we vatories would be clouded out. For a time received time at ESO telescopes, of which

Table 1: Usage of different observing modes during impact period.

ESO Campaign Obs. mode Setup July 2005 Observatory Telescope Instrument 2 3 4 5 6 7 8 9 10 11 Imaging Small field NQ-Filters x x x x x x x x VLT/LSO UT3/3.6-m VISIR/TIMMI2 AO LM-Filters x x x x x VLT UT4 NACO AO JHK-Filters x x (x) x x x x x VLT UT4 NACO/SINFONI Small field JHK-Filters x x x x x x x VLT/LSO NTT/UT1 SOFI/ISAAC Small field BVR-Filters x x x x x x x x x VLT UT1/UT2 FORS1/FORS2 Small field Comet. Filters x x x x x x x LSO NTT EMMI Wide field BVRI-Filters x x x x x x x LSO 2.2-m WFI Wide field NB-Filters x x LSO 2.2-m WFI Spectroscopy Low Disp. LSS N-Band x x x x x x x x x VLT/LSO UT3/3.6-m VISIR/TIMMI2 AO long slit L-Band x VLT UT1/UT4 ISAAC/NACO AO IFU/LSS JHK-Band x x VLT UT4 NACO/SINFONI Low Disp. LSS JHK-Band x x x x x x x x LSO NTT SOFI Low Disp. LSS 370–920 nm x x x x x x x x x x VLT/LSO UT1/UT2/NTT FORS1/FORS2/EMMI High Disp. SSS 304–1040 nm x x x x x x x x x x VLT UT2 UVES Polarimetry Imaging linear JHK-Band x x x LSO NTT SOFI Imaging linear NB visible x x VLT UT2 FORS1 Spectro. linear 400–900 nm x x VLT UT2 FORS1 Spectro. circular 400–900 nm x VLT UT2 FORS1

The Messenger 121 – September 2005 13 Reports from Observers Käufl H.-U. et al., Deep Impact at ESO Telescopes

four were closely coordinated and per- range from 300 nm to 20 micron and ex- perfectly suited for such a unique and un- formed by an international team of come- ploring almost all possible observing predictable event. tary experts, experienced observers, data techniques such as seeing and diffraction analysts and modelers. Two of the pro- limited direct imaging through broad- posals (PIs: Hainaut, Käufl) characterised band, narrowband, and special cometary Paranal and La Silla, the pre-impact status of the comet, filters, spectroscopy using long-slits/low- part of a world observatory the other two (PIs: Böhnhardt, Rauer) dispersion, short-slit/high-dispersion and focused on the observation of the im- integral field optics as well as imaging Even if the Deep Impact spacecraft had pact event and its aftermath. During the and spectro-polarimetry with linear and missed the comet, the data set would be impact period the team used all seven circular polarisation optics. Table 1 pro- absolutely unique, as the worldwide telescopes currently operated by ESO at vides an overview of the usage of the campaign to observe Comet 9P/Tempel 1 Paranal and La Silla, i.e. the four 8.2-m different observing modes applied during involved all major observatories and unit telescopes of the ESO Very Large the impact period at the various ESO tele- various spacecraft. Hubble Space Tele-

Telescope (VLT) and the 3.6-m, the NTT scopes and instruments.y In this context scope, Spitzer Infrared Space Obser- t and 2.2-m telescopes at La Silla (LSO). it is interesting to note thati one of the ref- vatory, and Chandra and XMM/Newton in

Altogether 11 instruments at these tele- erence science cases fors the VLT was X-rays, to name just the most impor- scopes delivered scientific measurements to repeat an observationaln campaign such tant observatory type missions observed e

covering the widest possible wavelength as SL9 and indeed, the t VLT proved to be in parallel and even ESA’s Rosetta space- n I –R6 –R5 –R4 –R3 –R2 e 1.5

CN v i t ] 1 –2 days

– 1 c a e +1 days l

s 10 2 e

m +6 days

– 0.5 c R g

r 0 e 6 0 3870 3871 3872 3873 1 1 –

[ Wavelength (Å) x u l 1 F Figure 4 (above): Section of the UVES spectrum of the CN (0,0) band in Comet 9P/Tempel 1. The black thick line is the observed spectrum (50 hours); the thin (red) line is the best fitting synthetic spectrum of 5 4 4 5 –1 × 10 –5 × 10 0 5 × 10 1 × 10 12C14N, 12C15N and 13C14N obtained for an isotopic Projected Nucleocentric distance [km] mixture 12C/13C = (95 ± 15) and 14N/15N = (145 ± 20). The lines of 12C15N are identified by the short ticks Figure 3 (above): Comparison of the spatial profiles and those of 13C14N by the longer ticks. The quantum along the slit for the integrated CN emission numbers of the R lines of 12C14N are also indicated. (at ~ 390 nm) on the nights July 2/3 (black), July 4/5 This is only the second time that the C and N ratios (red) and July 9/10 (green). The impact plume can have been measured in a Jupiter-family comet. The be seen in CN and dust, being more extended in the ratios are the same as in Oort Cloud comets. This will CN than in the dust continuum (not shown here). put important and interesting constraints on the for- The distances are positive towards the sun direction mation history of Jupiter-family comets. (Jehin et al., (Rauer et al., in preparation). in preparation).

1.4 Figure 5 (left): Dust ejecta with SOFI: The left image shows the extra signal after impact (“normal” comet coma subtracted, July 4 – July 2) of the dust ejecta in J-band. The differences in the radial profiles of JHK 1.2 images (right) of the ejecta cloud suggest that heavier dust is concentrated closer to the nucleus than the lighter one, since the K-band profile peaks at 2000 km projected nucleus distance while the J-band 1 reaches maximum around 10 000 km distance. From the flux enhancement of the ejecta cloud over pre- impact level, we deduce a total dust production by the impact that compares to about 5–10 h of “normal” 0.8 undisturbed activity of the nucleus at the time of the encounter (this assumes similar dust grain properties and a mean expansion velocity of about 100–200 m/s) (Tozzi et al., in preparation). 0.6 0 5 000 10 000 15 000 km

14 The Messenger 121 – September 2005 Figure 6: A set of four quasi-true-colour composite July 4 July 5 images with FORS2. The dust cloud from the impact was detected in broadband and narrowband images until July 8, 2005. On July 4 it had a semi-spherical shape expanding at the front edge with an average speed of about 200 m/s into the south-western coma quadrant (velocity of brightness maximum moved at about 120 m/s). The main axis of the cloud was at position angle (PA) of about 225 deg, which indicates that the impact happened below the orbital plane of the comet. The cloud expansion was slowed by radiation pressure during the subsequent days and reached a maximum expansion in the Sun direction of about 30 000 km. This distance compares to dust grains with a ratio of radiation pressure to gravity β ~ 0.3 (assuming an initial expansion speed of 200 m/s). Latest as of July 6, 2005, the dust started to be expelled into the tail direction (PA = 111 deg). The sudden drop in surface brightness between July 6 and 7 is yet to be understood.

– the nucleus albedo is 4 % July 6 July 7 – the crater formation was most likely “gravity controlled”; this implies that the tensile strength of comet material is of order of ~ 100 Pa, very similar to the limits set by the tidal disruption of comet Shoemaker/Levy 9 by Jupiter – the impact angle was 50–70 deg (measured in the optical convention, from the surface normal) – the nuclear shape model is not finished, but the size is 3.5 × 5 km (A’Hearn, IAUS 229) – the infrared spectrum during the first

seconds after impact showed: H2O, HCN, (CH)x, CO2 (CO2/H2O) ~ 0.08, CH3CN (Sunshine, IAUS 229) craft – en route for a rendezvous with available two conference rooms, and two Comet 67P/Churyumov-Gerasimenko in data servers were set up, so that data As a selection of ESO results a few spec- January 2014 took part in the scientific reduction could start immediately. At this tra and images are presented here. In observations of the impact event. Thanks point nearly all data are reduced in general one can note that 4–5 days after to the coordination through Karen Meech the sense that the instrumental signatures impact all impact related signatures at the University of Hawaii and colleagues have been removed and the data have had disappeared in the “noise” of normal at the University of Maryland a dedicated been calibrated and converted into physi- cometary activity. web-server was available and a perma- cal units. Now the real work has to begin, nent multi-site videoconference moderat- that is to compare the data to theoretical ed from the control room of the NASA- models and to put them into context Dust grain characterisation 3-m Infrared Telescope Facility (IRTF) on with data from the spacecraft and from Mauna Kea provided the tools to com- other observatories. The ESO data set The characterisation of the physical and municate preliminary results and to have was already partially presented at the IAU chemical properties of the dust grains mutual consultation on the observations. Symposium 229, August 7–12, 2005 was attempted – among others (dynam- Thus very effective observing was possi- Asteroids, Comets, Meteors (one oral pre- ics, near-IR) – through mid-IR and po- ble and duplication of observations min- sentation and four posters). larimetric observations of the cometary imised. coma before and after impact. The following results from the spacecraft Mid-IR: By black-body fitting to mid-IR were reported at the recent IAU Sympo- filter photometry of the cometary coma Observational results sium 229: obtained with VISIR (VLT) and TIMMI2 – the impact did release 1–2 * 107 kg (LSO), a significant temperature increase All scientists involved in the ESO cam- of dust with a particle size < 10 µm; of the dust was seen post-impact (330 K). paign met after the observations in Santi- particles were pre-existing, i.e. not The dust temperature dropped to the ago at the ESO-Vitacura premises for the result of impact shattering of larger pre-impact level (280–290 K) as of July 6, a 10-day “conclave”. ESO had made structures 2005. However, the overall mid-IR flux,

The Messenger 121 – September 2005 15 Reports from Observers Käufl H.-U. et al., Deep Impact at ESO Telescopes

measured in the very inner coma (3–5ǥ), was higher from July 4–7, 2005 and re- turned to the pre-impact state only there- after. The N-band spectra of the inner coma reveal a silicate emission with different profile shape pre- and post-impact. Preliminary modelling indicates the presence of a large amount of absorbing (car- bon-like) material and an enhancement of amorphous and crystalline silicates in the post-impact dust. Furthermore, the post- impact dust seems to be enriched in crystalline silicates and displays a shallower size distribution (indicating larger grains present). Polarimetry: The linear polarisation of the dust was found to be 7.5 and 0 % (Stokes Q and U, respectively) in the visible Figure 7: Sample images from TIMMI2 before and wavelength range. The polarisation did after impact: the left image was taken on July 3 not change across the coma within 00h38 UT while the right image was recorded on July 4 19h38 UT. The filter was the OCLI 11.9 µm filter, ~ 7000 km projected distance from the showing the strongest variations after the impact. The nucleus and was found the same on pixel scale in both cases is 0.2ǥ/pix (130 km at the July 3, 2005 (before impact) and July 5, 7, comet), N up E right. The right image was taken in 9, 2005 (after impact). Using spectro- daytime. polarimetric observations (July 5 + 9, 2005) we could not detect any wavelength dependence of the linear polarisation over the wavelength range ~ 400–850 nm. shown here (as well as the VISIR data) Synergies in Space, Time, and Wave- Moreover, the post-impact dust was thus refer to material which either length” will take place August 7–10, 2006 found not to be circularly polarised over has been released hours after the impact at the Palace of The Royal Academies the wavelength and distance range men- (fresh material under the impact site?), for Science and the Arts in Brussels (for tioned above (July 8, 2005). or is very slowly moving or even gravita- more information consult http://www.eso. tional bound to the nucleus. (Käufl et al., org/~hukaufl/deepimpact.html). The in preparation). workshop will be organized by the Vrije TIMMI2 observations Universiteit Brussels and ESO.

Thanks to daytime observing, the com- Outlook and future work et could be observed from La Silla Acknowledgements 3–4 hours before Paranal. Indeed the At this point a series of special publica- TIMMI2 data are most likely the first On behalf of all scientists involved in the campaign we tions in Science is under way. Once wish to thank the observatory staff for “a job well data taken after impact with a profession- results of the spacecraft are published done”. In spite of all the “extras” asked for by this un- al telescope west of Greenwich! While in refereed journals we can start to as- usual and demanding campaign we felt a very positive the comet coma appears clearly brighter semble the global picture from all ob- attitude towards this project, including a genuine in the “after-impact” frames it is not interest in the results of the observations. We appreci- servations. Back during the Jupiter-SL9 ate the outstanding professionalism and dedication entirely clear if this is due to the impact or event, the analysis of all observational of everybody involved: everything worked perfectly for normal activity. Ground-based mid-IR data was severely handicapped as the this campaign. After the observations, in Vitacura we observations cannot detect a signal for impact areas were just behind the visi- found excellent working conditions and a warm hospi- tality. distances exceeding typically ~ 4 arcsec ble limb of Jupiter. Astronomers thus did or 2 600 km due to sensitivity limitations. not know the physical details of the im- Assuming a “canonical” outflow velocity of pact and the viewing geometry was awk- References 200 m/s this in turn implies that ground- ward. The DI spacecraft data, however based thermal IR observations are sensi- A’Hearn M. F. et al. 2005, Space Science Reviews, will provide us with the “ground truth” of Volume 117, Issue 1–2, pp. 1–21 tive only to material (dust) produced by the impact and the associated physics. Hampton, D. L. et al. 2005, Space Science the comet in an interval of 10–15 000 s This will make the analysis much clearer. Reviews, Volume 117, Issue 1–2, pp. 43–93 before observation. This has to be kept in However, a synthesis of this unprec- Meech, K. J. et al. 2005, Space Science Reviews, Volume 117, Issue 1–2, pp. 297–334 mind when comparing any mid-IR data edented worldwide multi-wavelength data set obtained from the ground with optical, set is required to uncover synergies. Note: For in-depth reading on the subject, near-IR or data obtained by the Spitzer To that end a dedicated workshop “Deep http://deepimpact.eso.org/ is a good starting point. space-based observatory. TIMMI2 data Impact as a World Observatory Event –

16 The Messenger 121 – September 2005 Reports from Observers

A Triple Asteroid System

Artist’s impression of the triple asteroid system. One of the thousands of minor planets orbiting the Sun has been found to have its own mini planetary system. Astrono- mer Franck Marchis (University of Califor- nia, Berkeley) and his colleagues at the Observatoire de Paris1 have discovered the first triple asteroid system – two small asteroids orbiting a larger one known since 1866 as 87 Sylvia2.

“Since double asteroids seem to be common, people have been looking for multiple asteroid systems for a long time,” said Marchis. “I couldn't believe we found one.”

The discovery was made with NACO on the VLT. Using the observatory’s Service Observing Mode, Marchis and his colleagues obtained images of many asteroids over a six-month period.

One of these asteroids was 87 Sylvia, which has been known to be double since 2001, from observations made by Mike and newly discovered moonlet, orbiting bits around it. “Because of the way they Brown and Jean-Luc Margot with the about 710 km from Sylvia, is Remus, a form, we expect to see more multiple Keck telescope. The astronomers used body only 7 km across and circling Sylvia asteroid systems like this.” NACO to observe Sylvia on 27 occasions, every 33 hours. The second, Romulus, over a two-month period. On each of orbits at about 1360 km in 87.6 hours Marchis and his colleagues reported their the images, the known small companion and measures about 18 km across. discovery in the August 11 issue of was seen, allowing Marchis and his col- the journal Nature, simultaneously with an leagues to precisely compute its orbit. But The asteroid 87 Sylvia is one of the largest announcement that day at the Asteroid on 12 of the images, the astronomers known from the asteroid main belt, and Comet Meteor conference in Armação also found a closer and smaller compan- is located about 3.5 times further away dos Búzios, Rio de Janeiro state, Brazil. ion. 87 Sylvia is thus not double but triple! from the Sun than the Earth, between the orbits of Mars and Jupiter. The wealth (Based on ESO Press Release 21/05) Because 87 Sylvia was named after Rhea of details provided by the NACO images Sylvia, the mythical mother of the found- show that 87 Sylvia is shaped like a lumpy ers of Rome, Marchis proposed nam- potato, measuring 380 × 260 × 230 km. ing the twin moons after those founders: It is spinning at a rapid rate, once every Romulus and Remus. The International 5 hours and 11 minutes. Astronomical Union has approved the names. The observations of the moonlets’ orbits allow the astronomers to precisely calcu- Sylvia’s moons are considerably smaller, late the mass and density of Sylvia. With a orbiting in nearly circular orbits and in density only 20 % higher than the density the same plane and direction. The closest of water, it is likely composed of water ice and rubble from a primordial asteroid. “It could be up to 60 per cent empty space,” 1 The team is composed of Franck Marchis (University of California, Berkeley, USA) and Pascal Descamps, said co-discoverer Daniel Hestroffer. “It is Daniel Hestroffer, and Jerome Berthier (Observatoire most probably a ‘rubble-pile’ asteroid”, de Paris, France). Marchis added. These asteroids are loose aggregations of rock, presumably the re- 2 87 Sylvia is the 87th minor planet discovered. It was first observed from the Observatory of Madras (India) sult of a collision. The new asteroid on May 16, 1866, by the Government Astronomer formed later by accumulation of large A composite image showing the positions of Remus Norman R. Pogson. It was common in the early days fragments while the moonlets are proba- and Romulus around 87 Sylvia on nine different to assign a name – mostly feminine – from the bly debris left over from the collision nights as seen on NACO images. It clearly reveals the mythology to newly found asteroids. Pogson select- orbits of the two moonlets. The inset shows the ed a name from the list furnished to him by Sir John that were captured by the newly formed potato shape of 87 Sylvia. The field of view is 2 arc- Herschel. asteroid and eventually settled into or- sec. North is up and East is left.

The Messenger 121 – September 2005 17 Reports from Observers

FLAMES Observations of Old Open Clusters: Constraints on the Evolution of the Galactic Disc and Mixing Processes in Stars

Sofia Randich1 Open clusters are populous groups of (IMF), or gas flows are still not well known. Angela Bragaglia 2 stars whose members have the same For example, the question of how much Livio Pastori 3 age, chemical composition, and dis- chaotic early accretion of dwarf satellites Loredana Prisinzano4 tance from the Sun. Hence, they provide and star-forming clouds, on one side, Paola Sestito 2 homogeneous samples to investigate and a smoother, dissipative gas accretion, several important issues related to stel- Paolo Spanò 4 on the other side, concurred to build up lar and Galactic evolution. We present Sandro Villanova 5 the Galaxy is currently one of the hot- here an overview and preliminary results Giovanni Carraro 6 test open issues concerning galaxy for- 2 of a VLT/FLAMES programme aimed Eugenio Carretta at a detailed study of seven old clusters. mation (Freeman & Bland-Hawthorn 2 Donatella Romano Our two main goals are the determina- 2002). Radial metallicity gradients and Simone Zaggia 7 tion of the radial abundance gradients in their evolution with Galactic age are Roberto Pallavicini 4 the Galactic disc and their evolution among the most useful observational con- Luca Pasquini 8 with age, and the investigation of inter- straints that one can put on those pro- Francesca Primas 8 nal mixing processes in stars similar cesses and, more in general, on Galactic Gianpiero Tagliaferri 3 to our Sun. chemical evolution (GCE) models (Tosi Monica Tosi 2 2000). For example, the predicted gradients can flatten or steepen in time, de- Galactic open clusters (OCs) cover large pending on the different model assump- 7 1 INAF – Osservatorio Astrofisico di intervals in age (from a few × 10 years tions on the SFH and infall processes to several billion years), metallicity (from Arcetri, Italy (e.g., Portinari & Chiosi 1999). Hence, about five times below to about twice 2 INAF – Osservatorio Astronomico empirically proving the flattening or steep- above the solar value), and position in the di Bologna, Italy ening of the gradients with time appears 3 Galactic disc (up to 22 kpc from the INAF – Osservatorio Astronomico Galactic centre). OCs represent vital labo- crucial. Knowledge of [α/Fe] abundance di Brera, Italy ratories for stellar astronomy because ratios and their evolution as well repre- 4 INAF – Osservatorio Astronomico they provide a means to study the individ- sents an important tool to trace a galaxy di Palermo, Italy ual properties of stars as a function of SFH and IMF, since the timescales of the 5 Dipartimento di Astronomia, Università age, metallicity, and mass. On the other variations of the abundance ratios depend di Padova, Italy hand, the global properties of old OCs, on both the SFH and the IMF. More 6 Departamento de Astronomía, and in particular their chemical composi- specifically, the mass function affects the Universidad de Chile, Chile tion, provide reliable information on the ratios of elements synthesised by stars 7 INAF – Osservatorio Astronomico status of the disc at early epochs, which of different mass, while the star formation di Trieste, Italy is crucial for a better understanding of the rate regulates the timing of their produc- 8 ESO overall Galaxy formation and evolution. tion.

In this article we describe a FLAMES proj- Several abundance studies exist for the ect on old Galactic OCs aimed at ad- solar neighbourhood, but we still know dressing two distinct issues: namely, i) the formation and evolution of the Galactic little about the chemical composition in disc, and ii) the study of the evolution of other parts of the disc. The mean metal- lithium abundances and mixing processes licity gradient has been determined based in solar analogues. Final results and con- on different spectroscopic studies of clusions require completion of the analysis a variety of tracers (H II regions, B stars, of our large data set and detailed com- planetary nebulae (PNe), OCs). However, parison with both results available in the these samples provide partial results, literature and theoretical models. Here mainly because they can only sample a we provide an overview of the project limited range of distances and ages. In together with a few examples of prelimi- particular, indicators such as H II regions nary results, with the purpose of em- and B-type stars give independent esti- phasising the wealth of information that mates of the shape and magnitude of the can be achieved with a relatively small present-day Galactic gradients, while amount of observing time with FLAMES. information about the temporal variation of the gradients can be obtained only The astrophysical problems from PNe and old OCs. Also, uncertainties arise since different classes of ob- 1. Formation and evolution of the jects (and even objects belonging to the Galactic disc same class) are often analysed using different methods, resulting in possible sys- Various important quantities related to the tematic effects in the derived gradients evolution of the Galaxy, such as star-for- and in discrepant results. There is indeed mation history (SFH), initial mass function a hot debate over whether OCs really

18 The Messenger 121 – September 2005 present a metallicity gradient or rather a otherwise similar stars do not deplete the tioned above could not be investigated in discontinuous distribution of metals same amount of Li. Our Sun has a very a comprehensive and systematic way, due with Galactocentric distance (Twarog et al. low Li abundance, a factor of about 100 to the lack of accurate, homogeneous 1997). Finally, very little is known about below the meteoritic value which is in- abundance data sets for large samples of [α/Fe] ratios, their radial distribution, and dicative of the initial solar abundance, but stars in OCs well sampling the age-me- evolution with Galactic age (Friel 2005). It several stars with similar or even older tallicity-Galactocentric distance parameter thus becomes mandatory to use a large, age exist with a much higher Li. A large space. By exploiting FLAMES capabili- homogeneous OC sample – like that dispersion in Li abundances is also ties, our project aims at simultaneously presented in this paper – in order to shed seen among MS stars in the solar-age, acquiring high-quality spectra of signifi- more light onto the actual behaviour solar-metallicity cluster M 67 (Jones et cant samples of evolved (7–14 per cluster) of the metallicity distribution in the disc. al. 1999). and unevolved (100–200 per cluster) members of seven well-selected OCs. This puzzling scenario and, in particular Our specific goals are: 2. Evolution of lithium and mixing the evidence for MS Li depletion, has – The investigation of the [Fe/H] radial in solar-type stars motivated theoreticians to introduce non- gradient in the disc and its evolution standard or extra-mixing physics in the with Galactic age, based on a homoge- Lithium (Li) is destroyed by proton cap- models. Several mechanisms have been neous abundance analysis of evolved ture at the relatively low temperature proposed, together with the suggestion cluster members; of 2.5 MK and it is depleted from stellar that an additional parameter, besides age, – The determination of abundances of atmospheres when a mechanism is mass, and chemical composition, must α and Fe-peak elements and their ra- present that is able to transport surface affect Li depletion. Stellar rotation and/or tios to Fe, to study their radial distribu- material down to the deeper stellar rotational history appear as the most like- tion and evolution with Galactic age; interiors where the temperature is high ly additional parameters, and rotational – The determination of cluster member- enough for Li burning. Thus, although mixing is the extra-mixing process that ship of photometric cluster candidates the absolute abundance of this element is presently receives the largest consensus; that will allow us to “clean” colour- very small (3 × 10–9 in number with nevertheless, this process is not able magnitude diagrams. This is crucial in respect to hydrogen, at most), measure- to explain other observational results (for order to (re)derive secure and homo- ments of Li abundance in stars are example beryllium abundances in M 67) geneous cluster parameters (age, dis- unique tracers of internal mixing mecha- and, as a matter of fact, the mechanism tance, reddening); nisms. With the exception of very low driving MS Li depletion in solar-type stars – The determination of Li abundances in mass, fully convective stars, the physics remains elusive (Randich 2005). We also MS and/or TO cluster members, in driving Li depletion in stars is not well mention that the effects of chemical com- order to carry out a systematic study of understood. Measured Li abundances in position on Li depletion which are predict- the evolution of Li in solar-type stars stars of different spectral types (from ed by theory are still rather poorly con- and its dependence on chemical com- early-F to late-K) and evolutionary stages strained. position. (from pre-main-sequence – PMS – to evolved clump stars) strongly challenge Understanding mixing processes at work The multiplexing capability of FLAMES the prediction of “standard” models of in Pop. I stars and their dependence and its high efficiency are perfectly suited stellar evolution. With this term we refer on metals is important not only for a bet- to our purposes. Radial velocities and to those models that include convection, ter comprehension of stellar structure Li abundances (from the Li 670.8 nm line) but neglect other transport phenomena and evolution; it also provides a key to are determined from Giraffe spectra of such as diffusion, gravity waves, rotation investigate whether this mechanism may unevolved cluster stars, while the detailed and angular momentum loss. work for metal-poor Pop. II stars and, chemical analysis is obtained from possibly, to explain the origin of the dis- UVES spectra of cluster clump or RGB Focusing on stars similar to our Sun, crepancy between primordial 7Li abun- members. standard models predict that they should dance predicted by WMAP and Big Bang deplete most of their Li while on the Nucleosynthesis and the stellar val- Giraffe has been used in MEDUSA mode PMS, that they should not undergo any ue based on Pop. II star Li abundances with the high-resolution gratings depletion on the main sequence (MS), (Romano et al. 2003). covering the ranges 630.8–670.1 nm, and that stars with the same age, mass, 660.7–679.7 nm and 647.0–679.0 nm. and chemical composition should de- With UVES CDs covering 476.0–684.0 nm plete a similar amount of Li. At variance The goals and target clusters and 660.0–1060.0 nm have been used, with these predictions, observations allowing us to target, besides several iron of Li in field and cluster stars carried out Until the advent of multiplex facilities on lines, the forbidden lines of O around during the last 20 years have shown that 8-m-class telescopes, high spectral reso- 630.0 nm, Na at 568.2–568.8 nm and solar-type stars suffer very little PMS Li lution studies of OCs were very time 615.4–616.0 nm, Mg and Ca from several depletion, but do deplete Li on the MS. consuming and limited to small samples lines, Si from lines around 570.0 nm. Li depletion is not a monotonic function of of bright stars in the closest clusters. The O I triplet at 777.4–777.7 nm, the age; rather it seems to be bimodal and As a consequence, the open issues men- Na lines at 813–819.4 nm, the N ones

The Messenger 121 – September 2005 19 Reports from Observers Randich S. et al., FLAMES Observations of Old Open Clusters

12 13 around 800.0 nm, and the C/ C iso- Cluster Age (Gyr) [Fe/H] RGC(kpc) D (kpc) E (B-V) Table 1: Sample clusters in increasing tope from the CN lines around 800.0 nm NGC 3960 0.9 –0.34 8.0 1.7 0.29 age order. Cluster parameters (age, [Fe/H], Galactocentric distance, dis- NGC 2324 0.9 –0.15 11.6 3.6 0.20 are included in the red UVES setting. tance from the Sun, and reddening) NGC 2477 1.0 –0.13 8.9 1.3 0.28 have been retrieved from different The sample clusters are listed in Table 1, NGC 2660 1.1 –0.18 9.2 2.8 0.31 sources in the literature. [Fe/H] values while in Figure 1 we show, as an exam- NGC 6253 3.0 +0.36 7.0 1.5 0.20 for most of the clusters have been derived from low-resolution spectra or Be 29 3.5 –0.44 22.0 14.8 0.16 ple, the colour-magnitude diagram of photometry and are not on the same Berkeley 32, the most metal-poor cluster Be 32 7.2 –0.50 11.3 3.1 0.15 scale. One of the goals of the present in our sample. Table 1 shows that the se- project is the homogeneous determina- lected clusters span large intervals in age, tion of cluster parameters and abundances. distance, and metallicity. Our sample will be complemented by a sample of three additional old OCs observed in the context of the Ital-FLAMES Guaranteed Time (GTO) programme (Pallavicini et al. 2005). Figure 1: V vs. V-I colour-magnitude diagram of Berkeley 32. Photometry 12 was retrieved from the literature. Two observing runs were approved for Two FLAMES pointings on this cluster this programme, for a total of about were obtained and stars observed in 50 hrs; one of them was performed in both pointings are shown in the figure. Service Mode, while the other one has UVES targets are denoted as blue 14 symbols, while Giraffe/Medusa targets been carried out in Visitor Mode. The are indicated as red symbols. data were reduced using the UVES pipeline within MIDAS and the Giraffe BLDRS pipeline. Examples of extracted UVES V 16 spectra of clump stars in NGC 3960 are plotted in Figure 2, while in Figure 3 we show Giraffe spectra of 16 MS stars in NGC 6253 around the Li I 670.8 nm 18 spectral region.

Results: first examples 0.5 1 1.5 Cluster membership V–I

In Figure 4 we show the radial velocity histograms obtained from the analysis of Giraffe spectra of 196 and 111 photo- Figure 2: UVES spectra of six clump metric candidate members of NGC 6253 NGC 3960 members of NGC 3960 in a 100 Å wide c9 region around Hα. Besides Hα, a few and Be 32 respectively. In both cases lines employed for the chemical analy- the distribution of radial velocities is char- sis are indicated. Abundance analy- acterised by a well-defined, narrow peak, c8 sis has been performed using MOOG implying a small velocity dispersion. Our and Kurucz model atmospheres. The sample stars have magnitudes V ~ 13 velocity determination for Be 32 is in good c6 and the spectra are the sum of two agreement with available velocities for 45 minute long exposures. evolved cluster members from the literature. To our knowledge no radial velocity c5 measurements have so far been performed for NGC 6253 and thus our estimate represents the first determination c4 of the cluster velocity. Noticeably, for both clusters the percentage of confirmed c3 members is rather low (slightly above 50 %).

Fe I Ni I Ti I Ca I Fe I Ni I A zoom of the colour-magnitude diagram Hα of Be 32 is shown in Figure 5; radial-velocity members are denoted as red dots. 6520 6540 6560 6580 Wavelength (Å) The figure indicates that, when removing

20 The Messenger 121 – September 2005 Figure 3: Giraffe spectra of 16 MS members of the metal-rich cluster NGC 6253. The Li I 670.8 nm and Ca I 671.8 nm features are indicated in the upper row. Magnitudes of the sample stars are in the range V = 15.5–16.5 and they were exposed for 45 min. Note the varying strength of the Li feature for stars with similar Ca I line (i.e. of similar spectral type).

non-members, the cluster sequence of x 1 u l confirmed members remains rather broad. f l a This suggests the presence of a signifi- 0.8 Li I Li I Li I Li I m r

cant fraction of photometric binaries o n and/or differential reddening. Interestingly, 0.6 Ca I Ca I Ca I Ca I we note that all but one of the stars bluer

x 1

and brighter than the TO, which were u l f classified as possible blue stragglers be- l a 0.8 longing to the cluster, are instead non- m r o

members. n 0.6

x 1 u l

Chemical abundances: NGC 3960 f l a 0.8 m NGC 3960 is one of the youngest and r o closest clusters in our sample. It hence n 0.6 represents an important extreme for the determination of the radial metallicity x 1 u l f

gradient and its evolution with Galactic l a age. A photometric study of this cluster 0.8 m r was recently carried out by Prisinzano et o n al. (2004), who concluded that the clus- 0.6 ter has an age between 0.9 and 1.4 Gyr 670.5 671 671.5 670.5 671 671.5 670.5 671 671.5 670.5 671 671.5 and is characterised by differential wavelength (nm) wavelength (nm) wavelength (nm) wavelength (nm) reddening. Spectroscopic studies of the cluster are therefore also important to better constrain its parameters.

NGC 6253 Be 32 From the analysis of the UVES spectra of Cluster velocity –28.1 +/– 1.3 (km/s) Cluster velocity 105.1 +/– 1.1 (km/s) Field stars velocity –19 +/– 42 (km/s) Field stars velocity 66 +/– 33 (km/s)

seven clump stars we derive an iron con- 0 8 Number of observed stars 196 0 Number of observed stars 111 6 tent close to solar ([Fe/H] = –0.02 ± 0.11), Possible cluster members 105 Possible cluster members 58 at variance with earlier reports of a some- Contamination 7 Contamination 2 0 5 what lower metallicity ([Fe/H] = –0.34) 0 6 s r a t

based on modest-resolution spectra. This 0 s 4 f o

result evidences the need for abundance r e b 0 0 determinations using high-resolution m 4 3 u spectra. Also, the previous low-metallicity n 0

estimate for NGC 3960 made this clus- 2 0 ter one of the most metal-poor ones at its 2 0 age and Galactocentric distance, sig- 1 nificantly contributing to the dispersion in 0 the [Fe/H] vs. age and RGC diagrams at 0 relatively young ages and small distances. –100 –50 0 50 0 20 40 60 80 100 120 140 v (km/s) v (km/s) This dispersion is considerably reduced Helio Helio when considering the value of [Fe/H] derived by us. Figure 4: Left: Histogram of heliocentric radial veloci- stars were determined either with our own proce- ties of candidate NGC 6253 members observed dures within the MIDAS or IRAF1 contexts or using the with Giraffe. The solid line indicates the best fit of the appropriate recipe within the BLDRS software. As Our [X/Fe] ratios represent the first de- observed distribution obtained using a maximum a by-product, we were able to assess the accuracy of terminations of these quantities for likelihood fitting procedure. The resulting mean veloci- the latter and its dependence on the set-up (or spec- NGC 3960; we find values close to solar ties for the cluster and field stars are indicated, tral range), the reference templates, and the S/N ratio ratios for Mg, Si, Ti, and Ni, while alumi- together with their standard deviations, the number of of the spectrum. Right: Same as left-hand panel, possible cluster members, and expected number but the histogram of radial velocities for Berkeley 32 is nium is slightly underabundant and Na, of contaminants. Individual radial velocities of cluster shown. Ca and Cr appear somewhat enhanced. The mean [α/Fe] ratio is almost solar.

1 IRAF is distributed by the National Optical Astronom- ical Observatory, which is operated by the Associa- tion of Universities for Research in Astronomy, under contract with the National Science Foundation.

The Messenger 121 – September 2005 21 Reports from Observers Randich S. et al., FLAMES Observations of Old Open Clusters

Lithium in NGC 6253 15 Figure 5: Zoom of the colour-magnitude diagram of Berkeley 32. Only Giraffe targets are plotted. Red NGC 6253 is the most metal rich cluster and black filled circles indicate in our sample and provides a good target confirmed radial-velocity members and to better investigate the dependence of stars rejected as members. Li depletion on metals, which is predicted 16 by both standard and non-standard models. In particular, at the high metallicity of this cluster a larger amount of Li depletion for a given mass is expected. V 17 In Figure 6 we show the canonical plot of Li abundances vs. effective temperature for NGC 6253 MS stars together with the distribution of M 67. Besides the normal trend of decreasing Li abundance 18 with decreasing temperature (mass), two important features are evident in the figure: 1. Li abundances for stars warmer 0.6 0.8 1 1.2 than about 5 800 K are characterised by V–I a small dispersion, much narrower than that observed among M 67 members. On the other hand, cooler stars do show a dispersion comparable to M 67. Together with the results for other old clusters, this Figure 6: Lithium abundances 3 suggests that the presence of the scat- (log n(Li) = log n(Li)/n(H) + 12) as a function of effective temperature (Teff) ter and the temperature/mass at which it for NGC 6253 (red symbols) and is seen are related to some (still unknown) M 67 (black symbols). The sample of characteristics of the cluster, rather than NGC 6253 includes only stars cov- ) i 2 ered by one of the two pointings on this to the cluster age. The complete analysis L ( cluster, that were confirmed as mem- n of the whole Li data set will shed more bers, and that are fainter than V = 15.5, g light on this aspect. 2. Stars in the upper o i.e., are still on the MS and have l envelope of NGC 6253 are not more not undergone any post-MS Li dilution. Li depleted than stars in the upper enve- 1 Data for M 67 were taken from the literature. NGC 6253 Li abundances lope of the about a factor of two more were determined using the method metal poor M 67, suggesting that, at vari- that we have used in other studies and ance with model predictions, even a consistently with M 67. rather large difference in the overall metal 0 6200 6000 58005600 content does not affect the rate of T (K) Li depletion, at least in the temperature eff range considered here.

In summary, the few preliminary results ters and abundances will let us put strin- Pallavicini, R., Spanò, P., Prisinzano, L., Randich, S., discussed above already attest the gent and robust empirical constraints and Sestito, P., 2005, in Chemical Abundances and Mixing in Stars in the Milky Way and its Satellites, strength of our approach. Radial velocity on models of Galactic disc formation and L. Pasquini and S. Randich eds., ESO Astrophysics analysis has been completed for all the evolution, as well as on the physics Symposia, Springer, in press sample clusters and we are now ready to at work in the interiors of solar analogues Portinari, L., and Chiosi, C. 1999, A&A 350, 829 determine cluster parameters in a homo- during the MS phases. Several spin-off Prisinzano, L., Micela, G., Sciortino, S., Favata, F. 2004, A&A 417, 945 geneous way using the synthetic colour- scientific topics will also be addressed. Randich, S. 2005, in Chemical Abundances and magnitude diagram technique developed Mixing in Stars in the Milky Way and its Satellites, by us. At the same time, we will complete L. Pasquini and S. Randich eds., ESO Astro- the analysis of UVES spectra to derive References physics Symposia, Springer, in press Romano, D., Tosi, M., Matteucci, F., Chiappini, C. the chemical composition of the whole Freeman, K., and Bland-Hawthorn, J. 2002, 2005, MNRAS 346, 295 sample and the analysis of Giraffe spectra ARA&A 40, 487 Tosi, M. 2000 in The Evolution of the Milky Way: Stars for Li determination. Spectra of the clus- Friel, E. 2005, in Chemical Abundances and Mixing versus Clusters, F. Matteucci and F. Giovannelli ters observed in the context of the in Stars in the Milky Way and its Satellites, eds. (Dordrecht: Kluwer), p. 505 Twarog, B. A., Ashman, K. M., Anthony-Twarog, B. J. GTO project mentioned above are also L. Pasquini and S. Randich eds., ESO Astrophysics Symposia, Springer, in press 1997, AJ 114, 2556 being consistently analysed. The final Jones, B. F., Fisher, D., Soderblom, D. R. 1999, homogeneous data set of cluster parame- AJ 117, 330

22 The Messenger 121 – September 2005 Reports from Observers

Measuring Improved Distances to Nearby Galaxies: The Araucaria Project

Wolfgang Gieren1 Grzegorz Pietrzynski1 Fabio Bresolin 2 Rolf-Peter Kudritzki 2 Dante Minniti 3 Miguel Urbaneja 2 Igor Soszynski1 Jesper Storm 4 Pascal Fouqué 5 Giuseppe Bono 6 Alistair Walker 7 José García1

1 Universidad de Concepción, Chile 2 Institute for Astronomy, Hawaii, USA 3 Universidad Católica, Chile 4 Astrophysikalisches Institut Potsdam, Germany 5 Observatoire Midi-Pyrénées, France 6 Osservatorio Astronomico di Roma, Italy 7 Cerro Tololo Inter-American Observatory, Chile

Figure 1: The spiral galaxy NGC 55 in the Sculptor Group, one of the target galaxies of the Araucaria An intense use of ESO telescopes over Project. The presence of an abundant young stellar the past years has allowed us to make population is revealed by the many blue objects con- significant improvements in the charac- centrated towards the disc of this galaxy. terisation of stellar populations, and in the determination of the distances of of nearby galaxies in order to calibrate number of important scientific results nearby galaxies. We report on recent far-reaching secondary methods of dis- have emerged from the abundant data progress on the use of Cepheid vari- tance measurement which could be used obtained with ESO telescopes, some ables and blue supergiant stars for the to determine the distances to galaxies of which we will briefly describe in this accurate measurement of galaxy dis- remote enough to find an unbiased value article. In this progress report, we will tances. This work will finally lead to a of H0. Their very successful work was focus on two types of distance indicators, significant reduction of the uncertainty hampered by the fact that Cepheid vari- the pulsating Cepheid variables, and the on the Hubble constant, which meas- ables are not a perfect instrument for extremely luminous blue supergiant stars. ures the current rate of expansion of the distance measurement. Cepheids, like Universe. other stellar standard candles, are affected to some degree by the environmental Progress on the Cepheid properties of their host galaxies, most period-luminosity relation The measurement of distances to astro- notably abundances of the heavy ele- nomical objects is a fundamental problem ments, and the ages of the stellar popula- The radially pulsating and relatively cool ever since humanity began to look at the tions. Such effects must be taken into ac- Cepheid supergiant stars exhibit a well- stars. Knowledge of precise distances count if truly accurate distances to nearby known relation between their mean in- to galaxies is important for the study of a galaxies are to be measured. With this trinsic luminosity, and their pulsation peri- broad range of astrophysical phenomena, motivation in mind, our group set out, ods – the famous period-luminosity including the true energy outputs of lu- a few years ago, to thoroughly investigate (PL) relation, which is normally written in minous sources; it is also fundamental for the environmental dependences of a the form M = a log P + b, where M is establishing accurate cosmological pa- number of stellar distance indicators, the mean absolute magnitude (in a given rameters which describe the actual state, including Cepheids, blue supergiants, RR photometric band), and P the period and history of the Universe. One par- Lyrae stars, red clump giants, and the (in days). With the PL relation calibrated, ameter of particular interest is the Hubble tip of the red giant branch (TRGB) magni- the mean luminosities of Cepheids, constant H0 which measures the cur- tude in the Araucaria Project (http://ifa. and thus their distances, can be inferred rent acceleration of the expanding Uni- hawaii.edu/~bresolin/Araucaria/). This from their periods. In order to determine verse. Some ten years ago, the HST Key project is a necessary complement to the the dependence of the PL relation on Project on the Extragalactic Distance HST Key Project. Over the past two metallicity, we have been conducting sur- Scale (Freedman et al. 2001) set out to years, the Araucaria Project has obtained veys for Cepheids in a number of spiral measure Cepheid distances to a sample a Large Programme status at ESO, and a and irregular galaxies of widely different

The Messenger 121 – September 2005 23 Reports from Observers Gieren W. et al., Measuring Improved Distances to Nearby Galaxies

Figure 2: The Cepheid period-luminosity relation defined by Cepheid variables in NGC 55, in the I-band. The period P is in days. From wide-field images taken on about 50 different nights, we discovered 81 Cepheids with periods longer than 10 days – these are the first Cepheid variables ever discovered in this galaxy. Differential reddening in this rather inclined galaxy is likely to contribute significantly to the observed scatter. This effect should be greatly reduced in the near-infrared PL relations we are currently measuring from VLT/ISAAC images. metallicities in the Local Group, and in the Sculptor Group. From a comparative NGC 55 study of the PL relations exhibited by the Cepheids in the different galaxies, in a 19 variety of optical and near-infrared photometric bands, we can expect to determine both, the effect of metallicity on the slope, and on the zero point of the PL 20 I relation, and to filter out the most appro- [ m a

priate photometric band for distance g work in which the effect is minimised. ] 21 So far, we have completed optical (BVI) surveys for Cepheids over the whole spatial extents for the Local Group galaxies NGC 6822 (Pietrzynski et al. 2004), 1 1.2 1.4 1.6 1.8 2 NGC 3109 and WLM; these data comple- logP ment previous surveys for Cepheids in other Local Group irregular galaxies (LMC, SMC, and IC 1613). In Sculptor, Cepheid NGC 55 Cep 7 P = 67.13 d surveys have been completed for the spiral galaxies NGC 300 (Gieren et al. 2004),

NGC 55, NGC 247, and NGC 7793. 19 21 The wide-field imaging data used in these surveys were obtained at the ESO 2.2-m telescope and WFI instrument, with a strong complement from the Polish 1.3-m 21.5 telescope and mosaic camera at 0.5 1 1.5 2 0 0.5 1 1.5 2 Las Campanas Observatory, and the 4-m phase phase Blanco telescope and mosaic camera at CTIO. In all Araucaria target galaxies, NGC 55 Cep 14 P = 45.99 d including those in the Local Group, we 19 20.5 were able to very substantially enlarge the number of known Cepheids, and in par- 21

ticular find long-period ones which carry 19,5

V [

the strongest weight in the distance m 21.5

[

a ] determinations. In three of the four Sculp- g 20 ] tor Group spiral galaxies, we have dis- 22 covered the first Cepheid variables ever. 0 0.5 1 1.5 2 0 0.5 1 1.5 2 phase phase An example is NGC 55 (Figure 1); in this galaxy, we have detected 81 Cepheids with periods in the range 10–100 days Figure 3: Phased light curves in V- and I-bands for which define a tight PL relation (Figure 2). two of the Cepheids we discovered in NGC 55. The periods are indicated on the plots. Such data lead In Figure 3, we show the light curves to a very precise determination of the mean magni- of two of these variables in the V- and I- tudes of the variables.

bands, obtained from our mosaic images I

[

a g

taken on about 50 different nights. As an One first conclusion from these data is witha the direct Baade-Wesselink-type

] g example of the improvement on the that in the optical V and I bands, the infrared] surface brightness technique Cepheid census in the Local Group, we slopes of the PL relations observed in all (Gieren et al. 2005a) has furthermore pro- show in Figure 4 (see next page) the these different galaxies are consis- vided strong evidence that the slope of PL relation defined by some 100 Cephe- tent with the slopes defined by the LMC the PL relation keeps being independent ids in NGC 3109, most of them discov- Cepheids observed in the OGLE-II Project of metallicity up to the solar abundance ered in the Araucaria Project from data (Udalski 2000), arguing for a very small shown by the Milky Way Cepheids. This is taken during 80 nights at the Polish 1.3-m metallicity effect (consistent with a null ef- an especially important result since many telescope on Las Campanas. In contrast fect) on the PL relation slope in the [Fe/H] of the massive spiral galaxies in the to the more massive spiral NGC 55, range from about – 1.0 dex to – 0.3 dex, HST Key Project have near-solar heavy- NGC 3109 does not contain a population spanned by the young populations of our element abundances. Application of of very long-period Cepheids. target galaxies. Recently, our distance the LMC Cepheid slopes in V and I to the work on LMC and Milky Way Cepheids observed Cepheid PL relations in such

24 The Messenger 121 – September 2005 Figure 5: The near-infrared PL relations in J- and K-bands determined from VLT/ISAAC data for Cepheids in the Sculptor galaxy NGC 300. The variables were previously discovered by Pietrzynski et al. (2002) from wide-field images obtained at the ESO-MPI 2.2-m telescope. Each Cepheid was Figure 4: The Cepheid PL relation in the I-band for the observed at two different epochs and its mean mag- Local Group galaxy NGC 3109. Most of the Cepheids nitude determined with the method of Soszynski in this plot were discovered in the Araucaria Project. et al. (2005). The data fit very well the PL relations in Note that NGC 3109, in contrast to NGC 55, does not J and K as obtained for the LMC Cepheids by contain truly long-period Cepheids – the longest ob- Persson et al. (2004). The slopes of the solid lines served period is 31 days. were taken from this work.

19 NGC 3109 NGC 300

20 19 I K [ m [ m a g 21 a ] g 20 ]

21 22

0.6 0.8 1 1.2 1.4 logP

18 galaxies should therefore not cause any important systematic problem.

Very recently (Bresolin et al. 2005a), we 19 have been testing the effect blending J

of Cepheids with nearby projected neigh- [ m a bour stars in the crowded images of dis- g 20 tant galaxies has, by comparing ground- ] based photometry of Cepheids in NGC 300 from ESO-WFI data to BVI images of the same Cepheids obtained with the 21 Hubble Space Telescope and ACS. In the case of NGC 300, with its distance of 1 1.2 1.4 1.6 1.8 2 logP close to 2 Mpc, the systematic effect of blending on the distance derived from the ground-based images is found to be only ~ 2 per cent. The main reason is that in the LMC with the Polish 1.3-m tele- and provide a definitive answer about long-period Cepheids are intrinsically scope on Las Campanas which is expect- the reality of a period break in the relation. bright enough to outshine nearly all of the ed to discover a large number of new close companions on the images, making bright, long-period Cepheids close to the their relative contributions to the Cepheid bar. These data, which cover most of Cepheid work in the near-infrared flux measured on ground-based images the spatial extent of the LMC and which insignificant in most cases. This is good will become available in 2007, will also There are at least three substantial advan- news for ground-based Cepheid distance decide the nagging question of whether tages when Cepheid distance work is car- work on relatively distant galaxies. the LMC Cepheid PL relation shows ried out in near-infrared bands. The first a break near 10 days, as claimed by obvious advantage is the strong reduction Since the LMC Cepheids are currently Sandage et al. (2004). Such a departure of the effect of dust absorption. A second providing the fiducial PL relations for from a uniform slope over the whole advantage is that Cepheid light curves in the distance determination of other galax- period range, if real, would evidently con- the near-infrared, and particularly in the ies, owing to the very large number of stitute a serious problem in the use of K-band, are more symmetrical than their Cepheids discovered by the OGLE-II and the Cepheid PL relation for distance work. optical light curves, and have smaller am- other microlensing projects, it is extremely If the break at 10 days turns out to be plitudes. This makes it possible to mea- important to establish the Cepheid PL re- real, new fiducial LMC PL relations must sure a Cepheid’s mean K-band brightness lations (in different bands) in the LMC with be established in the period range long- with a very good precision from just one the highest possible accuracy. Since wards of 10 days, which is the relevant random phase photometric observation, if the existing microlensing surveys have not range for the measurement of the dis- the star’s optical light curve and period is found many long-period Cepheids in the tances of galaxies beyond about 1 Mpc. known (Soszynski et al. 2005). K-band LMC, due to long integration times which Our current “LMC shallow Cepheid PL relations can therefore be determined overexposed any Cepheids longward survey” is expected to provide a signifi- very economically if the Cepheids of a of periods of ~ 30 days, we are currently cant improvement of the calibration of galaxy have been previously found and undertaking a “shallow” Cepheid survey the LMC Cepheid PL relation in V and I, characterised in the optical spectral range.

The Messenger 121 – September 2005 25 Reports from Observers Gieren W. et al., Measuring Improved Distances to Nearby Galaxies

In addition to these important advan- 1.4 I I I I I I I I tages, theoretical studies suggest an even I

I 1.6 e e I I I i I smaller dependence of the PL relation N H O S C O H on metallicity in the near-infrared, as com- 1.2 1.4 pared to optical wavelengths. 1.2 For these reasons, we have been under- 1.0

taking near-infrared follow-up imaging x 1.0 u for selected subsamples of long-period l Cepheids in most of the target galaxies F 0.8 e 0.8 v i

of our project. We have been obtaining t

a 3990 4045 4100 4280 4340 4440 6520 6570 6620 these images using VLT/ISAAC, and the l e 1.4 NTT with the SOFI instrument. Superb R I I I I I I I I e e e e I results are being obtained from these very i H S N II + O II H H N H high-quality data, as recently demon- 1.2 strated in the case of NGC 300. Figure 5 shows the PL relations in the J- and K- bands obtained from our VLT images 1.0 for this galaxy, which have led to a very accurate determination of the distance to NGC 300 by combining the near-infared 0.8 and optical data for this galaxy (Gieren et 4470 4510 4550 4590 4630 4670 4710 4850 4900 4950 5000 5050 al. 2005b; see also a recent August 1, Wavelength (Å) 2005 ESO Press Release). The work on NGC 300 has shown how essential in- are, however, considerable uncertainties Figure 6: The technique used to measure the abun- frared images are to achieve an accurate on the gas-phase abundance scale at dance of metals of blue supergiants is shown here. With the stellar gravity fixed by fits of model spectra to determination of the reddening of a high metallicity (around the solar value and the high-order Balmer lines and the effective tem- galaxy, including the contribution coming above), as encountered in the central perature determined from line diagnostics, the abun- from dust absorption inside the galaxy. regions of spiral galaxies (Bresolin et al. dances of different elements are varied in the models Only in this way can it be hoped to 2005b). Stellar abundance studies allow until the best fit (in yellow) to the observed spectrum (orange line) is obtained. The sensitivity to the achieve the final goal of the Araucaria us to circumvent this difficulty, although abundance is indicated in the lower part of the pan- Project, which is to measure the dis- the chemical analysis in young massive els, where models differing by ± 0.2 dex relative to the tances to nearby galaxies with a precision stars is a complex task, due to strong de- best-fitting model are compared. The effects of strong of at least 5 per cent, or better. partures from conditions of local thermo- stellar winds in this B3 supergiant in NGC 300 are visible in the Hα line, which is in emission (upper right). dynamic equilibrium and to the effects of stellar winds on the atmospheric struc- supergiant stars in NGC 300 (Urbaneja et Blue supergiants ture. It is important to note that both al. 2005). By combining our good-quality the blue supergiants and the H II regions data with modern stellar-atmosphere The spectroscopy of blue supergiants, the are young (< 10–20 million years) objects, analysis techniques for massive stars we brightest young stars visible in galaxies, and therefore the galactic chemical have been able to compare for the first and among the most massive, is an inte- abundances derived from them are rele- time in a galaxy located outside the Local gral part of the Araucaria Project. The vant for the study of young stellar Group the chemical abundance gradient goal of our detailed study of these stars is distance indicators, such as Cepheids. in its disc obtained independently from twofold: to measure chemical abundances the stellar analysis, and from the ionised of heavy elements and to develop and The analysis of the chemical composition gas (Figure 7). apply a new distance determination tech- of blue supergiants complements nique based on a small set of fundamen- the study of H II regions, which is limited The NGC 300 observations were carried tal stellar parameters. mostly to the abundances of oxygen, out utilising the multi-object spectroscop- nitrogen and sulphur, by providing infor- ic capabilities of FORS at the VLT, yield- Gathering information on the metal con- mation not only for these elements, but ing intermediate-resolution spectra of sev- tent of galaxies is essential to obtain also for additional species, such as eral dozens of stars in this galaxy (Bresolin accurate distances, since the techniques magnesium, iron and silicon. Model spec- et al. 2002). This observing strategy, re- used, such as the Cepheid PL relation, tra, calculated accounting for the pres- peated for all the galaxies included in could significantly depend on metallicity. ence of millions of atomic transitions, are the Araucaria Project, has allowed us to The chemical abundances in spiral and compared to the observed supergiant collect several hundred spectra of blue irregular galaxies are commonly obtained spectra to measure the abundances of supergiant candidates (the case of NGC from the spectroscopic analysis of giant these metals. An example of this pro- 247 in Sculptor is shown in Figure 8). H II regions, resulting from the photoioni- cedure is shown in Figure 6, taken from This represents an unprecedented sample sation of gas clouds by hot stars. There our chemical analysis of early B-type of extragalactic massive star spectra, of

26 The Messenger 121 – September 2005 Figure 7 (left): A comparison of the radial oxygen Log (O/H) + 12 abundance gradient in NGC 300 obtained from the 8.9 NGC 300 B supergiants (green star symbols) and the H II regions (orange disks). The oxygen abundance is in the 12 + log(O/H) scale, commonly adopted in nebular work (the solar value is ~ 8.7 on this scale), 8.7 while the horizontal coordinate is the deprojected galactocentric distance in units of the isophotal radius. The nebular abundances have been obtained from the emission line fluxes available in the literature and 8.5 adopting the Pettini & Pagel (2004) calibration of the R 23 abundance indicator.

8.3

Figure 8 (below): Over 60 blue supergiant candi- 8.1 dates have been observed spectroscopically in the Sculptor Group galaxy NGC 247, as indicated here on a mosaic derived from FORS images. The arrow points to the emission line star whose spectrum 7.9 R/R is shown in Figure 9. Candidates for the FORS/MXU 0 spectroscopic follow-up were selected from colours and magnitudes measured from 2.2-m telescope WFI 0.0 0.2 0.4 0.6 0.8 1.0 1.2 images.

great value for the immediate needs of the in V between –7 and –10), blue super- The Flux-weighted Gravity-Luminosity project (abundances and luminosities), giants are among the brightest stellar Relationship (FGLR) determined from our and for future research on normal B- and objects observed in galaxies, second only analysis of blue supergiants (spectral A-type supergiants, as well as on more to supernovae. The investigation of their types from early-B to mid-A) in galaxies of exotic, rare objects, like the extremely usefulness as extragalactic distance indi- the Local Group and in NGC 300 is shown luminous emission-line star we discovered cators, therefore, is a natural component in Figure 10. The calibration we have ob- in NGC 247 (Figure 9). A dedicated ana- of the Araucaria Project. A simple but tained can be used to measure distances lysis technique is being developed by our powerful technique was developed by to galaxies where spectra and apparent group in order to cope with the large Kudritzki et al. (2003), who found that the magnitudes of blue supergiants are avail- 4 amount of stars for which we are deriving flux-weighted gravity g/Teff (the gravity g able. This independent spectroscopic the basic parameters (gravities, tempera- and the effective temperature Teff are both method, despite the complexities involved tures and metallicities). determined from the spectra) is strongly in the data analysis, provides simulta- correlated with the intrinsic luminosity neously the luminosities, as well as the Thanks to their extreme luminosity in the of blue supergiants, and appears to be chemical abundances of the target optical range (with absolute magnitudes quite insensitive to metallicity variations. stars. In this respect, the FGLR has an

The Messenger 121 – September 2005 27 Reports from Observers Gieren W. et al., Measuring Improved Distances to Nearby Galaxies β H x u L

F Figure 9: The FORS2 spectrum of an extremely lumi-

nous (MV ~ –9.3) blue supergiant star in NGC 247. d A strong stellar wind is responsible for the emission e 3 lines visible throughout the spectrum (a nebular com-

s ponent is also present for the Balmer lines), which is i

l reminiscent of the spectra of Luminous Blue Variables. Most of these features are due to Fe II, as identified a γ by the vertical bars. H

m 2 r I I e I I a ε δ o F C H H N 1

4000 4500 5000 Wavelength (Å)

Figure 10: The Flux-weighted Gravity-Luminosity relationship is plotted here for blue supergiants analysed –10 in the Local Group and in NGC 300. The legend Milky Way shows the meaning of the different symbols used. The LMC data are taken from Kudritzki et al. (2003), except SMC for the early B-type supergiants in NGC 300, which M31 are taken from Urbaneja et al. (2005). M33 – A Ia –9 NGC 3621 NGC 6822 NGC 300 – early B

l NGC 300 – B8–A4 o b

M –8

–7

1.8 1.6 1.4 1.2 1.0 4 Log (g/Teff,4) (cgs)

advantage over the photometric meth- research. Last not least, we want to thank the differ- Gieren, W., Pietrzynski, G., Soszynski, I. et al. 2005b, ods of distance determination (Cepheids, ent members of the OGLE Project for helping out with ApJ 628, 695 the observations for this programme at the Polish Kudritzki, R. P., Bresolin, F., Przybilla, N. 2003, TRGB, etc.), in that it allows us to ac- telescope on Las Campanas. ApJ 582, L83 count directly for the effects that metallici- Persson, S. E., Madore, B. F., Krzeminski, W. et al. ty has on the distances derived. 2004, AJ 128, 2239 References Pettini, M., Pagel, B. E. J. 2004, MNRAS 348, L59 Pietrzynski, G., Gieren, W., Fouqué, P., Pont, F. 2002, Bresolin, F., Gieren, W., Kudritzki, R. P. et al. 2002, AJ 123, 789 Acknowledgements ApJ 567, 277 Pietrzynski, G., Gieren, W., Udalski, A. et al. 2004, Bresolin, F., Pietrzynski, G., Gieren, W., Kudritzki, R. P. AJ 128, 2815 We thank the ESO Observing Programmes Commit- 2005a, ApJ, in press Sandage, A., Tammann, G. A., Reindl, B. 2004, tee for the generous allocation of observing time Bresolin, F., Schaerer, D., González-Delgado, R. M., A&A 424, 43 to our project. It is a pleasure to thank ESO staff on Stasinska, G. 2005b, A&A, in press Soszynski, I., Gieren, W., Pietrzynski, G. 2005, Paranal and La Silla for their expert collaboration in Freedman, W. L. et al. 2001, ApJ 553, 47 PASP 117, 823 obtaining those observations which were scheduled in Gieren, W., Pietrzynski, G., Walker, A. et al. 2004, Udalski, A. 2000, AcA 50, 279 service mode. Wolfgang Gieren, Grzegorz Pietrzynski, AJ 128, 1167 Urbaneja, M. A., Herrero, A., Bresolin, F. et al. 2005, and Dante Minniti acknowledge support from Gieren, W., Storm, J., Barnes III, T.G. et al. 2005a, ApJ 622, 862 the Chilean FONDAP Center for Astrophysics for this ApJ 627, 224

28 The Messenger 121 – September 2005 Reports from Observers

Early Galaxy Evolution: Report on UVES Studies of a New Class of Quasar Absorbers

1 Céline Péroux Quasar Miroslava Dessauges-Zavadsky 2 1 Sandro D’Odorico To earth Tae Sun Kim 3 Richard G. McMahon 3 Intervening gas H emission from quasar 1 ESO H absorption 2 Observatoire de Genève, Switzerland ‘Metal’ absorption lines 3 Institute of Astronomy, Cambridge University, United Kingdom

Distant galaxies can be studied using the imprints that their gaseous structures leave in the spectrum of a background quasar. These “quasar ab- 3500 4000 4500 5000 5500 6000 sorbers” provide a measure of both the Wavelength (Å) neutral gas and metallicity content of the Universe back to early cosmic times. Quasar absorbers are also an excellent Figure 1: Cartoon illustrating a quasar line of sight tool for measuring the abundances of along which various objects give rise to absorp- A newly defined class of quasar ab- tion features seen in the spectrum of the background sorbers, the sub-Damped Lyman-α Sys- a wide variety of elements over >90 % of quasar. The panel presents a typical quasar spectrum, tems, have been studied for the first the age of the Universe. In addition to showing the quasar continuum, emission lines, time using both the ESO archives providing information on individual ob- and the absorption lines produced by galaxies and jects, they can be used statistically to pro- intergalactic material that lie between the quasar and and new UVES/VLT data. This review the observer. The strongest N absorption at presents results from four years of vide measures of the cosmological evolu- H I λobs ~ 4600 Å is due to a Damped Lyman-α Absorber research on these systems and empha- tion of metals in the neutral gas phase. at z ~ 2.79 (Figure courtesy of John Webb). sises the scientific role played by the The so-called H I-column density weight- ever-growing ESO science archive. ed metallicity shows surprising results: contrary to virtually all chemical models, the most recent observations indicate al. 2001), we have suggested that Tracing the rate at which stars form over only mild evolution with redshift. Never- some fraction of the H I lies in systems cosmological scales still remains a theless, it is wellknown that such analyses below the traditional DLA definition. challenging observational task. An indirect are dominated by the main contributors We proposed to extend the definition to 19 –2 way to measure the assembly of galaxies to the H I mass. Therefore, it is important NH I >10 atoms cm and introduced is to probe the rate at which they convert that all the quasar absorbers containing the terminology “ sub-Damped Lyman-α their gas into stars. The neutral H I mass a significant fraction of H I gas are includ- systems” (sub-DLAs) in Péroux et al. in particular can be estimated from obser- ed to get a global metallicity estimate. 2003a. Such high column density systems vations of absorbers seen in the spec- are reportedly good tracers of galaxies: trum of background quasars. The most looking out through the Milky Way, many 19 20 remarkable property of these systems A new class of quasar absorbers lines of sight have 10 < NH I <2 × 10 is that their detection threshold is essen- atoms cm–2, reminding us that we actually tially redshift independent and only relies Quasar absorbers are sub-divided into live in a sub-DLA! on the properties of random luminous classes according to their column den- background sources (quasars or Gamma- sity, the number of hydrogen atoms per The study of sub-DLAs has been made Ray Bursts) observed up to early cosmo- unit area along the line of sight between possible only thanks to the advance- logical times (z > 6). Thus, unlike other the observer and the quasar (commonly ment of 8–10-m-class telescope related high-redshift galaxies (such as Ly-α emit- expressed in atoms cm–2). Therefore a technologies. Indeed high-resolution ters or Lyman Break Galaxies), these low column density cloud could either be spectroscopy is required to study sub- objects are selected regardless of their a small cloud with high density or a large DLAs. The Ultraviolet-Visual Echelle Spec- morphologies or intrinsic luminosities but cloud with low density. They are thus trograph UVES (D’Odorico et al. 2000) solely on their H I cross-sections (see believed to probe a variety of physical mounted on UT2 has played a key role in Figure 1). Therefore, they provide unbi- conditions including halos and discs recent developments of our understand- ased samples to measure the redshift of both dwarf and normal (proto)galaxies. ing of quasar absorbers, and sub-DLAs in Damped Lyman-α systems (hereafter particular. In 2001, we initiated a pro- evolution of ΩH I, the total amount of neu- 20 –2 tral gas expressed as a fraction of today’s DLAs) have NH I > 2 × 10 atoms cm gramme aimed at building and studying a critical density. and are the major contributors to the neu- homogeneous sample of sub-DLAs.

tral gas ΩH I. Nevertheless, based on a The overall goal of this ongoing project is new sample of z > 4 quasars (Péroux et to identify what can be learned about

The Messenger 121 – September 2005 29 Reports from Observers Péroux C. et al., Early Galaxy Evolution

Figure 2: Example of a normalised UVES/VLT spectrum of a high-redshift quasar. This velocity scale plot is centred at the sub-DLA position corresponding

to zabs = 3.078. The red line represents the Voigt profile model used to determine the quasar absorber 20 –2 column density: NH I = 1.62 × 10 atoms cm (Figure from Péroux et al. 2005). the early stages of galaxy evolution from abundance ratios observed in DLAs. The SDSSJ0124+0044 the study of the systems detected in ab- Sub z = 3.078 Ly1 first comprehensive sets of measure- sorption. ments of O I and C II in high NH I column density systems were given. Indeed, another advantage is that these elements

Global metallicity evolution N are well-defined in sub-DLAs while they o r m are almost always saturated in DLAs. a l i s

In a first step towards this aim, we took e These species, unaffected by dust deple-

d –20000 2000 advantage of the ESO VLT archive to build F tion, provide direct indicators of the abun- l

u Relative Velocity (km/s) a sample of sub-DLAs by reducing and x dances in quasar absorbers. analysing UVES archival Echelle quasar spectra available to us on July 2001. This represented a sample of 35 quasars, Cosmological evolution of H I gas mass log N(H I) > 20.3 22 of which were unbiased for our study. log N(H I) < 20.3 This work led to the discovery of 12 sub- In order to study the early stages of DLAs (Dessauges-Zavadsky et al. 2003). galaxy evolution, we selected a sample of Their chemical abundances were derived 17 z > 4 quasar lines of sight observed using Voigt profile fitting (see Figure 2 with UVES/VLT (Péroux et al. 2005). The 〉 ] D for an example) and photoionisation mod- L statistical properties of the resulting sam- A els from the CLOUDY software package ple of 21 new sub-DLAs were analysed in in order to determine the ionisation cor- combination with the sub-DLAs from the rection. We find that the correction is neg- previous ESO archive study. This homo- 19 ligible in systems with NH I > 3.2 × 10 – geneous sample allowed us to determine and lower than 0.3 dex for most elements 2 the redshift evolution of the number den- 19 19 in systems with 10 < NH I < 3.2 × 10 sity of DLAs and sub-DLAs. All these sys- 〈

–2 [

atoms cm . The abundances observed in F tems seem to be evolving in the redshift e / this sample of sub-DLAs were further 0 H 2 4 range from z = 5 to z ~ 3. Assuming that

– Redshift used to determine the global metallicity of 1 all the classes of absorbers arose from

H I gas in both DLAs and sub-DLAs. Figure 3: NH I column density-weighted mean metallic- the same parent population, estimates of ities for DLAs (green) and sub-DLAs (black). The We found that the metallicity redshift evo- the characteristic radii were provided. R୯ dotted bins are for constant NH I intervals and the solid lu-tion of absorbers as traced by [Fe/H] bins are for constant redshift intervals. The evolution increases with decreasing column density, 0 shows a slightly more pronounced slope of [〈Fe/HDLA〉] is possibly more pronounced for sub- and decreases with cosmological time for sub-DLAs (α = –0.40 ± 0.22) than for DLAs than for DLAs (Figure from Péroux et al. 2003b). for all systems. The sub-DLA downsizing –1 DLAs (α = –0.18 ± 0.12). In addition, the runs from R୯ = 40 h100 kpc at z = 4 to –1 H I-weighted mean metallicity was com- R୯ = 30 h100 kpc at z = 2. The redshift puted for DLAs and sub-DLAs. The evolu- evolution of the column density distribu- 19 –2 tion of [〈Fe/HDLA〉] might be stronger for tion, f(N,z), down to NH I = 10 cm sub-DLAs than for DLAs, and absorbers 0 was also presented for two different red- 21 –2 with NH I > 10 atoms cm appear to shift ranges (Figure 5). A departure be the less evolved (Figure 3). Observa- from the usual power law is observed in tional evidence supports the hypothe- the sub-DLA regime. 1 sis that this different behaviour is not due –

to the hidden effect of dust (Péroux et al. ] f(N,z) was further used to determine the H / e

2003b). F total H I gas mass in the Universe at z > 2 [

2 (Figure 6). The complete sample of sub- – A study of the metallicity evolution with DLAs shows that they are important at all metal line profile ionisation showed hints redshifts from z = 5 to z = 2 and that their of a correlation, whereby higher [Fe/H] contribution to the total gas mass ΩH I is

3 z < 2 ratios are associated with systems with – 2 < Z < 3 ~ 20 % (or more if compared with the lat- Z > 3 larger widths (Figure 4). This correlation est Sloan results). It appears that ΩH I could indicate either a recent activity 0 200400 600 800 observed in both DLAs and sub-DLAs at of star formation (and hence more enrich- Low Ionisation Width (km/s) high redshift (z > 2) is low compared ment) or a higher mass (higher rotational with the mass density observed in stars Figure 4: [Fe/H] as a function of the velocity width velocity being proportional to the mass of of the low-ionisation transition. The colours of the today, Ω୯. The possibility that large num- the system). Abundance ratios for [Si/Fe], symbol depict different redshift ranges. The open bers of quasar absorbers are missing [O/Fe], [C/Fe] and [Al/Fe] were determined sym-bols are for DLAs and the filled symbols are for in optically selected quasar surveys is still and compared with two different sets of sub-DLAs. The boxes represent the mean in a given hotly debated. While radio surveys looking velocity interval with rms errors and suggest an in- models of the chemical evolution of galax- crease of metallicity towards larger widths of the low for DLAs in quasar samples without ies. Overall, these appear to resemble ionisation species. (Figure from Péroux et al. 2003b). optical limiting magnitudes (Ellison et al.

30 The Messenger 121 – September 2005 Figure 5: Column density distributions for two redshift ranges down to the sub-DLA definition. The horizontal error bars are the bin sizes and the vertical error bars represent the uncertainties. The blue dotted bins are predictions from Péroux et al. (2003a), while 19 20 –2 the red bins at 10 < NH I < 2 × 10 atoms cm correspond to the direct observations from the sample of sub-DLAs. The black bins represent DLAs (Figure from Péroux et al. 2005). Redshift 543 2 10.5 0

8 Stellar Mass Density H I Mass Density 6

× [H = 65]

1 o 0 8 4 × 1 0 M 8 a s s D e n s i – – t

1.78 < z < 3.5 3.5 < z < 5.0 y 2 2 4 4

18 20 22 18 20 22 0 0510 Log N Log N H I H I Time [Gyr] – – L L 2 2 o o 2 2 g g Figure 6: Observable baryons in the Universe as a 2 f f ( ( function of time. The green curve represents the mass × N N 1 , , z

z density in stars integrated from the Star Formation 0 ) ) Rate (SFR). The error bars represent the mass density – – in H I gas as derived from quasar absorbers de- 2 2 0 0 convolved from the local critical density (Figure from Péroux et al. 2005). – 2003)– show that there are not a large DLAs being dustier than their sub-DLAs used to search for new sub-DLAs already 1 1 8 number8 of DLAs missing, our expecta- counterparts, hence preventing the selec- observed with ESO facilities but so tions are that high-redshift galaxies should tion of their background quasar. If con- far unstudied. This type of research illus- be dusty. It should be emphasised how- firmed, this can be explained by the fact trates the role that the ever-growing ESO ever that there are two separate issues: that in sub-DLAs, the Zn column density archive plays for science. i) what is the dust content of the quasar threshold does not combine with the 20 –2 absorbers we know of today and ii) what NH I threshold NH I > 2 × 10 atoms cm fraction of the quasar absorbers are that prevents their detection. We therefore References missed because their background quasar propose that sub-DLAs might be asso- D’Odorico, S., Cristiani, S., Dekker, H., Hill, V., Kaufer, is not selected in the first place. ciated with the external parts of galaxies A., Kim, T., and Primas, F. 2000, SPIE4005, 121 which better traces the overall chemical Ellison, S. L., Pettini, M., Churchill, C. W., Hook, I. M., evolution of the Universe. Lopez, S., Rix, S. A., Shaver, P., Wall, J. V., and On the nature of sub-DLAs Yan, L. 2003, The Messenger 113, 64 Péroux, C., Storrie-Lombardi, L., McMahon, R., Irwin, M., and Hook, I. 2001, AJ 121, 1799 By assuming that both DLAs and sub- Future prospects Péroux, C., McMahon, R., Storrie-Lombardi, L., and DLAs trace the same underlying parent Irwin, M. 2003a, MNRAS 346, 1103 population, a natural explanation for the In order to investigate further this hypoth- Dessauges-Zavadsky, M., Péroux, C., Kim, T. S., D’Odorico, S., and McMahon, R. 2003, nature of sub-DLAs could be that they esis, we are currently investigating MNRAS 345, 447 are the outermost parts of galaxies. This the metallicity of sub-DLAs at z > 3, using Péroux, C., Dessauges-Zavadsky, M., D'’Odorico, S., is illustrated by the absorber size calcu- 10 of the 17 high-resolution UVES z > 4 Kim,T. S., and McMahon, R. 2003b, lations where the characteristic radius of quasar spectra from our sample for which MNRAS 345, 480 Péroux, C., Dessauges-Zavadsky, M., D’Odorico, S., –1 sub-DLAs is around 40 h100 kpc and the we have spectral coverage at wave- Kim,T .S., and McMahon, R., 2005, MNRAS, –1 one from DLAs is 20 h100 kpc. lengths red-wards of the quasar emission in press, astro-ph/0507353 lines. These systems will also be modelled The metallicity of sub-DLAs also seem to with CLOUDY in order to determine the differ from the one of classical DLAs. ionisation fraction of the gas. Smoothed particle Hydrodynamics simulations indicate that DLAs have one third In parallel, one of us (CP) is working on solar metallicity at z = 2.5 and should the UVES ESO VLT archive data with be even more metal-rich towards lower the aim to provide the user community redshifts. Indeed there are lines of evi- with a uniform data set of pipeline-re- dence pointing towards lower column duced products. The results will be made density quasar absorbers like sub-DLAs available to the public with the hope that being more metal-rich at z < 2 (Figure 3). it will encourage and facilitate the ESO This could be explained by classical archive usage. This new data set could be

The Messenger 121 – September 2005 31

Reports from Observers

A New Einstein Ring

Using the VLT, Rémi Cabanac and col- Figure 1: Composite image taken in leagues1 have discovered a new and very bands B and R with VLT/FORS, which reaches to magnitude 26. A zoom-in impressive Einstein ring. This cosmic mi- on the position of the newly found ring. rage, dubbed FOR J0332-3557, is seen towards the southern constellation Fornax (the Furnace), and is remarkable on at least two counts. First, it is a bright, almost complete Einstein ring. Second, it is the farthest of its type ever found.

“There are only a very few optical rings or arcs known, and even fewer in which the lens and the source are at large distance, i.e. more than about 7 000 million light years away (or half the present age of the Universe)”, says Rémi Cabanac, former ESO Fellow and now working at Observed Image Best Fitting Image the Canada-France-Hawaii Telescope. “Moreover, very few are nearly complete”, he adds. 2

The ring image extends to almost 3/4 of a circle. The lensing galaxy is located at a 1 distance of about 8 000 million light years c from us, while the source galaxy whose e s 0 c r light is distorted, is much farther away, at a 12 000 million light years. Thus, we see 1

this galaxy as it was when the universe – was only 12 % of its present age. The lens magnifies the source almost 13 times. 2 – The observations reveal the lensing galaxy 210–1 –2 210–1 –2 to be a rather quiet galaxy, 40 000 light arcsec arcsec years wide, with an old stellar population. The much more distant lensed gal- Figure 2: The left image is magnified and centred on yielded a redshift close to 1 for the lens (we see the axy, however, is extremely active, having the newly discovered Einstein ring. The image quality lens as it was when the Universe was half its present (“seeing”) of the R-band image is exceptional (0.5ǥ) size), and a redshift z = 3.8 for the ring (a back- recently experienced bursts of star and the image reveals the lensing system in stunning ground star-forming galaxy seen as it was when the formation. It is a compact galaxy some details. The central feature is the lens, a quiescent Universe was only 12 % of its present age. The lens- 7000 light years across. massive galaxy that distorts the light emitted by back- ing model indicates that the light of the source is ground sources. The large arc surrounding the central magnified at least 13 times. The right panel shows the lens is part of the Einstein ring created by a back- reconstructed image based on the model of the lens “Because the gravitational pull of matter ground source finely aligned with the lens. The reddish and the source; the ring is found to extend over 3/4 of bends the path of light rays, astronomical colour indicates that the redshift of the system is very a complete circle. objects – stars, galaxies and galaxy clus- large. FORS2 spectroscopy of the lensing system ters – can act like lenses, which magnify and severely distort the images of galaxies behind them, producing weird pictures In the most extreme case, where the ure of the mass within the lensing body, as in a hall of mirrors”, explains Chris foreground lensing galaxy and the back- and as a “magnifying glass”, it allows Lidman (ESO), co-discoverer of the new ground galaxy are exactly aligned, us to see details in objects which would cosmic mirage. the image of the background galaxy is otherwise be beyond the reach of current stretched into a perfect ring. Such telescopes. an image is known as an Einstein ring, because the formula for the bending From the image, co-worker David Valls- of light, first described in the early twenti- Gabaud (CFHT), using state-of-the-art 1 The paper describing this research has recently been published as a Letter to the Editor in Astronomy eth century by Chwolson and Link, uses modelling algorithms, was able to de- and Astrophysics, Volume 436, L21–L25, by Rémi A. Einstein’s theory of General Relativity. duce the mass of the galaxy acting as a Cabanac (CFHT, Hawaii), David Valls-Gabaud lens – it is almost one million million solar (Observatoire Midi-Pyrénées), Andreas Ortmann Gravitational lensing provides a very use- masses. Jaunsen (ESO Chile), Chris Lidman (ESO), and Helmut Jerjen (Mount Stromlo Observatory, ful tool with which to study the Universe. Australia). As a “weighing scale”, it provides a meas- (Based on ESO Press Photos 20b+c/05)

32 The Messenger 121 – September 2005 Reports from Observers

Resolved Spectroscopy of a z = 5 Gravitationally Lensed Galaxy with the VIMOS IFU

Mark Swinbank1 Galactic superwinds Starburst Figure 1: A cartoon of 1 Simple model for (Nebular emission lines) the dynamics of a galaxy Richard Bower with high-velocity super- 1 Galactic superwinds (SINFONI) Ian Smail (which currently lack UV ISM lines winds. By observing Ly α 1 Simon Morris spatial information) (VIMOS) emission and ISM lines Graham Smith 2 with VIMOS and the [O II] with SINFONI we will resolve all three compo- Redshifted nents of the galaxy and 1 superwind. ICC, Department of Physics, University to Observer Lyα of Durham [O II] (VIMOS) 2 Caltech Astronomy

–400 km/s +400 km/s We have used the VIMOS IFU to spatially resolve and study the star-forming, galactic superwinds and metal-enrichment properties in a highly magnified distant Lyman-break galaxies suggest three-dimensional structure of the outflow gravitationally lensed galaxy at z = 5 that, in these young systems, the collec- can be established. However, at these (i.e., seen when the Universe was only tive effects of intense star-formation ac- great distances even a massive galaxy ~ 10 % of its current age). These results tivity (and resulting supernovae) sweep up only spans 1ǥ on the sky and therefore ob- are allowing us to study galaxy forma- and drive a shell of material through the taining spatially resolved information is ex- tion and evolution in a level of detail galaxy disc, eventually bursting out of the tremely difficult. never before possible and provide excit- galaxy and accelerating into the ambi- ing possibilities for future studies of gal- ent intergalactic medium. In these ob- axies at these early times. servations the wind ejecta manifests itself Gravitational telescopes through the velocity offset between Lyα emission which traces the outflowing Fortunately nature provides us with a The problem with galaxy-formation mod- material and the rest-frame optical natural telescope with which we can els is not to understand why galaxies form emission lines (such as Hα and [O II]) study very distant galaxies in great detail. (this is due to the cooling and condens- which trace the star-forming (H II) regions Galaxy clusters magnify the images of ing of gas in dark matter halos), but to (Shapley et al. 2003). Indeed, velocity distant galaxies that serendipitously lie understand why such a small fraction of offsets of several hundred km/s have behind them (Smail et al. 1996, Ellis et al. baryons cool to form stars. Galaxy-for- been observed. If the energy of this wind 2001, Swinbank et al. 2003). This natural mation models which only include cooling is sufficient, the gas escapes the galax- magnification causes background galax- predict that more than 50 % of baryons ies’ potential and is not recaptured and ies to be strongly amplified and stretched. should form stars, yet a census of the plays no further role in galaxy formation. It provides us with the opportunity of baryons in the local Universe show that But the evidence for this superwind is studying young and intrinsically faint gal- less than 10 % are locked up in stars, rather indirect, and based on the assump- axies with a spatial resolution that cannot the rest is in a hot diffuse state, similar to tion that the outflow takes the form of be attained via conventional observations. that in the inter-cluster medium (Balogh an expanding spherical bubble surround- et al. 2001). To account for this puzzling ing the galaxy as illustrated in Figure 1 One of the most striking cases of grav- inefficiency requires some form of feed- (the current data are limited to traditional itational lensing is the (highly magnified) back – a method of expelling gas from long-slit spectroscopy, and are therefore z = 4.88 galaxy behind the rich lens- galaxies, preventing them from forming limited to one spatial dimension). Hence, ing cluster RCS0224-002 (Gladders et al. stars, and hence regulating galaxy forma- if the large velocity flow were instead with- 2002). The natural amplification caused tion (Bower et al. 2004, Swinbank et al. in the galaxy, the wind would be unlikely by the galaxy cluster has two effects 2005, Wilman et al. 2005). to escape the gravitational potential. Of (i) the image of the background galaxy is course, other interpretations are also pos- magnified at a fixed surface brightness sible: the outflow may be collimated and (i.e. the total brightness is increased) and, Regulating galaxy formation: feedback may not inhibit the inflow of gas in other (ii) the galaxy is not simply amplified, it directions; the wind might even stall and is also stretched, making it possible to The local Universe is a largely inert place, fall back onto the galaxy (a more ener- spatially resolve components of the galaxy with most activity long over. In order getic version of the Milky Way’s “galactic from the ground. to understand the feedback phenomenon fountain”). we must therefore look to the first galaxies that formed in the Universe (between The key to resolving this issue is to iden- This project 1 and 2 Gyr after the Big Bang, z = 3–5). tify these features in spatially resolved However, since they are very distant these out-flows around distant protogalaxies. In this article we report on the first results young galaxies are difficult to observe in By comparing the velocity field of the out- from a VLT VIMOS and SINFONI IFU study great detail. Recent deep observations of flow with that of the host galaxy the of the star-forming and kinematical prop-

The Messenger 121 – September 2005 33 Reports from Observers Swinbank M. et al., Resolved Spectroscopy of a z = 5 Gravitationally Lensed Galaxy

Figure 2: Left: HST false colour VI-band image of Right: Wavelength collapsed (white light) image the RCS0224-002 cluster core showing the central around the Lyα emission from the z = 4.88 arc made cluster galaxies as well as the multiple arcs and by collapsing the datacube between 7138 arclets. The multiply imaged z = 4.88 arc is labelled A, and 7188 Å. The z = 4.88 arc can clearly be seen in B and C, whilst the radial counter-image is labelled D the Lyα image. We also note that there appears to (see text). be another strong Lyα emitter to the North-East which is the counter image of the arc. erties in a z = 4.88 arc in the core of the lensing cluster RCS0224-002. In the 10 10 left-hand panel of Figure 2 we show the HST image of the cluster core and mark 5 8 the components of the arc A, B and C. D 5 As can be seen from the HST image, the c c e lensed galaxy (or arc) is over 12ǥ in length e 7 s s 0 A 0 c c r r 6 a and therefore is an ideal candidate for a integral field spectroscopy. The arc is mul- 5 tiply imaged, with component A appear- B –5 4 –5 3 ing to comprise a dense knot surrounded 2 by a halo of diffuse material (a foreground 1 –10 object is also superposed). The morphol- –10 ogy of components B and C mirror those C of A. –10 –5 0 5 10 –10 –5 0 5 10 arcsec arcsec The arc was observed with the VIMOS IFU on the VLT in December 2004. tive evidence for structure in the red wing namics and star-formation properties of Although the target was only observed for of the line, the blue cut-off occurs at con- primeval galaxies. The signal-to-noise 2 hours (the remaining 12 hours are due stant wavelength (the variations are that we expect from the final set of obser- to be completed in the current semester), less than 30 km/s). This is particularly im- vations (the remaining 12 hours of ob- the data already offer fascinating insight portant: the individual star-forming regions servations are expected to be completed into the nature of the Lyα emission in in the underlying galaxy are expected to in August/September 2005) will allow this galaxy. The VIMOS IFU provides a be moving at relative speeds in excess of us to tightly constrain the geometry of the three-dimensional (x, y, λ) “datacube” from 100 km/s (SINFONI observations are outflowing material and so test the geom- which we can investigate the spatial varia- scheduled to confirm and map this): if the etry of the superwind ejecta. We will tions in the Lyα and C IV emission lines superwind was localised to these re- also be able to investigate the dynamics and (eventually) UV interstellar absorption gions, the structure of the Lyα emission of the interstellar medium (spatially re- features. In turn these allow us to infer would vary significantly. In contrast, solved) through the absorption lines and the spatial distribution of star formation, the superwind model (Figure 1) predicits the metallicity of the gas through the metal abundance and to map the dy- that the sharp blue edge of the Lyα C IV/Lyα emission line ratios (continuum namics of the system’s components. emission line (which is formed by resonant and C IV emission are both detected in absorption in the outflow) will be un- the first 2 hours of data, but the remaining correlated with the velocity structure of 12 hours are required to boost the signal- Early results the host galaxy. The lack of structure to-noise and draw strong conclusions). suggests that the superwind “bubble” is Furthermore, by coupling this high-quality In Figure 2 we have projected the data- located well outside of the galaxy and is data with SINFONI IFU observations (also cube in the wavelength between 7138 escaping into inter-galactic space. expected to be taken in August/Septem- and 7188 Å so as to map the spatial dis- ber 2005) we will probe the [O II] emission tribution of the emission. It is clear that from this galaxy (which comes from the the Lyα emission line morphology traces Other primeval galaxies star-forming regions and therefore reflects that seen in the imaging, with the densest the underlying stellar populations which knots in the HST image being the bright- We can also scan the datacube for emis- are responsible for driving the superwind est in Lyα. sion lines from other galaxies within the in the galaxy; see Figure 1). These ground- VIMOS IFU field of view. Although the cur- breaking and exciting results will pro- By extracting a series of independent rent data are only partially complete, we vide valuable and important insights into spectra from the IFU datacube (Figure 3) have already identified at least two other this important phase of galaxy evolution. we can investigate the dynamics of the serendipitous sources in the field, includ- galaxy and the nature of any outflowing ing Lyα for z = 3.66 and z = 5.09 and as References material. Even the initial dataset, allows us well as [O II] from an arc at z = 1.0. to search for spatial variations in the Lyα Balogh et al. 2001, MNRAS 326, 1228 emission line. As seen in other young Bower et al. 2004, MNRAS 351, 63 Ellis et al. 2001, ApJ 560, 119 galaxies, the Lyα emission has a charac- Summary Gladders et al. 2002, AJ 123, 1 teristic asymmetric (P-Cyni) profile. To Shapley et al. 2003, ApJ 588, 65 examine the structure of the emission line, Whilst these results are in their early Smail et al. 1996, ApJ 469, 508 we compare the emission from the re- stages, they are showing the power of Swinbank et al. 2003, ApJ 598, 162 Swinbank et al. 2005, MNRAS 359, 401 gions marked 1–8 in Figure 2. The struc- coupling integral field spectroscopy Wilman et al. 2005, Nature 436, 227 ture of the line is remarkably constant with gravitationally lensed galaxies to spa- from region to region. While there is tenta- tially resolve and study the internal dy-

34 The Messenger 121 – September 2005 Figure 3: Spectra around the redshifted and intensity of the Lyα emission to Lyα emission from the eight com- study the superwind outflow. By ponents labelled in Figure 2. The red combining these measurements with dashed line shows the composite SINFONI spectroscopy of nebular spectra from the arc (scaled in flux). In emission lines we will investigate the each independant pixel of the data- star formation and chemical enrich- cube we use the position and shape ment of this young galaxy.

4000 4000 5000 4000

4 000 3000 3000 3000

3000 2 000 2000 2000 2000

1000 1000 1000 1000

0 0 0 0

1 v = 48 +/– 15 km/s 2 v = 45 +/– 15 km/s 3 v = 27 +/– 15 km/s 4 v = 7 +/– 15 km/s –1000 –1000 –1000 –1000 7100 7120 7140 7160 7180 7200 7100 7120 7140 7160 7180 7200 7100 7120 7140 7160 7180 7200 7100 7120 7140 7160 7180 7200

5000 5000 8000 1000

4000 4000 800 6000

3000 3000 600 4000 400 2000 2000

2000 200 1000 1000

0 0 0 0

5 v = 11 +/– 20 km/s 6 v = 32 +/– 15 km/s 7 v = 36 +/– 20 km/s –200 8 v = –1 +/– 30 km/s –1000 –1000 –2 000 7100 7120 7140 7160 7180 7200 7100 7120 7140 7160 7180 7200 7100 7120 7140 7160 7180 7200 7100 7120 7140 7160 7180 7200 Wavelength (Å) Wavelength (Å) Wavelength (Å) Wavelength (Å)

Farthest Known Gamma-Ray Burst

An Italian team of astronomers1 has used the Gamma-ray bursts (GRBs) are short flashes (Based on ESO Press Release 22/05) VLT to observe the afterglow of a Gamma-ray of energetic gamma rays lasting from less than burst that is the farthest known to date with a second to several minutes. They release a measured redshift of 6.3. “This also means a tremendous quantity of energy in this short that it is among the intrinsically brightest time, making them the most powerful events 18 Gamma-ray bursts ever observed”, said Guido since the Big Bang. It is now widely accepted IZ J H K Chincarini from INAF-Osservatorio Astronomico that the majority of the gamma-ray bursts di Brera and University of Milano-Bicocca signal the explosion of very massive, highly evolved stars that collapse into black holes. (Italy) and leader of a team that studied the ob- 20 ject with ESO’s Very Large Telescope. “Its e d u luminosity is such that within a few minutes it The Gamma-ray burst GRB050904 was first t i must have released 300 times more energy detected on September 4, 2005, by the n g than the Sun will release during its entire life of NASA/ASI/PPARC Swift satellite, which is dedi- a m 22 cated to the discovery of these powerful explo-

10 000 million years.” B

sions. Immediately after this detection, as- A 1 The MISTICI collaboration consists of astronomers tronomers in observatories worldwide tried to from Osservatorio Astronomico di Roma (INAF), identify the source by searching for the after- 24 Osservatorio Astronomico di Brera (INAF), Osserva- glow in the visible and/or near-infrared. The torio Astronomico di Arcetri (INAF), Università degli Italian group observed the object in the near- Studi di Milano – Bicocca, International School for Advanced Studies (SISSA) and Observatori Astro- infrared with ISAAC and in the visible with 5000 10000 15000 20000 25000 nòmic of Universitat de València (Spain). In particular, FORS2 on the VLT. By comparing the bright- Wavelength (Å) Angelo Antonelli, Daniele Malesani, Vincenzo ness of the source in the various observing Testa, Paolo D’Avanzo, Stefano Covino, Alberto bands (see Figure), the astronomers were able This figure shows the magnitude of the Gamma-ray Fernandez-Soto, Gianpiero Tagliaferri, Guido to deduce its redshift, and hence its distance. burst GRB 050904 as observed with FORS2 and Chincarini, Sergio Campana, Massimo Della Valle, “The value we derived has since then been ISAAC in the various filters. The bandpasses of the Felix Mirabel, and Luigi Stella were notably active ESO filters are overplotted as well as the best-fitting with the data analysis and observations. Prof. Guido confirmed by spectroscopic observations made template which allowed the astronomers to mea- Chincarini is the Italian Principal Investigator of the by another team using the Subaru telescope”, sure the photometric redshift. The clear drop of the Italian research on GRBs related to the Swift satellite, said Angelo Antonelli (Roma Observatory), an- flux of the object in the I-band compared to the which is funded by the Italian Space Agency (ASI). other member of the team. others is the telltale signature of a high-redshift object.

The Messenger 121 – September 2005 35 Photo: G. Hüdepohl, ESO

Reports from Observers

Surveying the High-Redshift Universe with the VIMOS IFU

Matt J. Jarvis1 object spectroscopy is usually the next The idea behind an IFU is to obtain con- Caroline van Breukelen1, 2 step to confirm redshifts and to gain tinuous coverage of a field in three dimen- Bram P. Venemans 2 a census of galaxies in the high-redshift sions, i.e. two spatial dimensions and a Richard J. Wilman3 Universe. third spectral dimension. This is analo- gous to taking a number of long-slit spec- A further technique which has come tra side-by-side all in one observation. 1 Astrophysics, Department of Physics, to fruition over the past decade, with the Integral-field observations are therefore Oxford, United Kingdom onset of 8- and 10-metre-class tele- able to provide an immediate 3-dimen- 2 Sterrewacht Leiden, The Netherlands scopes, is that of narrow-band imaging. sional view of structure in the Universe. 3 Department of Physics, University This method selects galaxies with The range of scales these IFUs may probe of Durham, United Kingdom strong emission lines at distinct distances, is from stellar populations in nearby galax- where the bright emission lines are ies to the furthest reaches of the observ- redshifted into a filter which has a typical able Universe. In this article we highlight We present results from a new method width of 5–10 nm. This essentially means the intriguing possibilities that large-area of exploring the distant Universe. We that the imaging instrument acts as a IFUs offer with respect to volume-limited use 3-D (integral-field) spectroscopy to very coarse spectrograph with 5–10 nm surveys of the high-redshift Universe. sample a large cosmological volume resolution. There are now many fields at a time when the Universe was less which have been targeted with this tech- than 3 billion years old to investigate the nique, most notably the deep narrow- A deep VIMOS IFU field and the evolution of star-formation activity in band survey to target Lyα emitting galax- star-formation history of the Universe the Universe. Within this study we also ies at z = 3.1 (Steidel et al. 2000) which discovered an obscured accreting black went on to find a new class of object – We initiated a pilot project with a deep, hole at high redshift which would not that of giant Lyα nebulae which are not nine-hour, VIMOS observation centred on have been identified with imaging stud- associated with powerful active galactic the high-redshift radio galaxy MRC0943- ies alone. This highlights the crucial nuclei. Other important surveys using 242 at a redshift of z = 2.92 in April 2003. role that integral-field spectroscopy may the narrow-band technique have been The aims of this project were to probe play in surveying the distant Universe in those which target powerful radio sources the giant-Lyα emitting halo surrounding the future. at high redshift. These have yielded the this source and the distribution of galaxies detection of overdensities of Lyα emitting within the volume probed by the IFU. galaxies at redshifts above 2. Blank-field Figure 1a shows the reconstructed Hunting for high-redshift galaxies searches have also yielded the detec- “broad-band” (i.e. with the spectral direction of large numbers of Lyα emitters tion collapsed over all frequencies) image The way in which galaxies form and at z = 5.7 (Ajiki et al. 2003) and one of the of the radio galaxy field. The central radio evolve, along with the stars they contain, highest redshift galaxies known to date galaxy can easily be seen in the centre of are crucial processes to investigate if at z = 6.6 (Hu et al. 2002). However, simi- the image. However, the only other we are to understand how the structure lar to the multi-colour method highlight- sources visible in this broad-band repre- we see in the Universe today builds up ed above, this technique also requires sentation are all relatively bright. Con- over cosmic time. For many years this has follow-up spectroscopy to confirm the versely, as can be seen in Figure 1b, if been the forte of deep multi-colour imag- Lyα emitting candidates. we now integrate over the spectral region ing observations, which have been used where the Lyα line is seen in the radio to find and investigate galaxies in the dis- It would obviously be extremely useful if galaxy spectrum [i.e. 121.6 nm × (1 + z)], tant Universe. This technique utilises the one could combine the imaging and the radio galaxy becomes much brighter. characteristic break in the continuum of a spectroscopy into a single observation, This highlights the benefit of the inte- galaxy below the Hydrogen Lyα emission which would not only overcome the gral-field approach when hunting for line at 121.6 nm and the Lyman-limit at various biases inherent to colour selected galaxies with bright emission lines at all 91.2 nm. Redward of these characteristic samples but would also expand on the redshifts. If we now split this data set wavelengths, a galaxy will be observed narrow redshift ranges which one can up into finer bins in wavelength then we to have a bright continuum, and observ- probe with narrow-band searches. We are are able to detect all the galaxies with ing the same patch of sky with a shorter now entering an era in astronomy where bright emission lines over the whole vol- wavelength filter, which lies below the this is achievable. In this article we de- ume. For Lyα emission this range is continuum break wavelength, a galaxy will scribe the first results from a deep, large 2.3 < z < 4.6, and for [O II] emission at a be much fainter and possibly not detect- volume search for emission-line galax- rest-frame wavelength of λ = 372.7 nm, ed at all. Therefore large samples of ies with the Visible Multi-Object Spectro- we probe 0.08 < z < 0.83. Therefore candidate high-redshift galaxies can be graph (VIMOS) on the ESO-VLT (http:// we can search for emission-line galaxies constructed in this way over large areas. www.eso.org/instruments/vimos/). over a large fraction of cosmic volume After catalogues of such objects have along the sightline of the IFU (e.g. for [O II] been built up, follow-up long-slit or multi- As well as being a large multi-object and Lyα emitters we probe ~ 50 % of spectrograph, VIMOS can also be used cosmic time since the Big Bang over the as a “large-area” integral-field unit (IFU). 1.2 square arcminute field-of-view).

38 The Messenger 121 – September 2005 Figure 1: (a) The two-dimensional image of our IFU field of view, integrated from 405–680 nm. (b) The same image integrated from 470–500 nm. The noisier regions in the corners of the images are due to a dither pattern used in the observations to enable accurate sky subtraction and bad pixel rejection, therefore the corners have had slightly less exposure time than the central, least noisy, region.

13 ǥ 13 ǥ

28ǥ 28ǥ n 43ǥ n 43

o ǥ o i i t t a a n n i i l l c c e e D 28o 58ǥ D 28o 58ǥ

13ǥ 13ǥ

–24° 29o 28ǥ –24° 29o 28ǥ 09h 45m 35.4s 34.4s 33.4s 32.4s 31.4s 30.5s 09h 45m 35.4s 34.4s 33.4s 32.4s 31.4s 30.5s Right Ascension Right Ascension

In order to achieve this we construct a ume. Construction of the luminosity func- By integrating over the Lyα luminosity sensitivity map across the whole field and tion is a non-trivial task for this type function we are therefore able to measure search for peaks in the clean parts of of data because those galaxies with bright the star-formation rate at the redshifts the optical spectrum, i.e. those regions emission lines can be seen to much covered by our data. This plot, along with devoid of bright sky lines and also where greater distance in the volume covered in the star-formation rate density derived by characteristic problems associated our data, thus the volume probed is other methods, is shown in Figure 3, for with the optics within the IFU are at a min- a strong function of the luminosity of the 0 < z < 6. Due to the fact that Lyα can be imum. This is carried out by fitting a poly- emission lines. Therefore, the luminosity- resonantly scattered and absorbed by nomial to the spectra at all points over dependent volume is measured using the neutral hydrogen around the source, the the field and detecting all of those peaks sensitivity function of the data cube. measured SFR from studies using Lyα in the spectra which deviate significantly are hard lower limits. Also, the presence from the noise estimates in each spectrum Figure 2 shows the Lyα luminosity func- of dust preferentially extinguishes the and each region within that spectrum. tion derived from this study compared to UV continuum emission, therefore even the luminosity function measured from multi-colour searches are prone to bi- This process enabled us to detect narrow-band studies and multi-colour se- ases which work to reduce the estimated 17 emission-line objects over the volume lection. One can see that our luminosity SFR. Therefore, we also show the esti- probed with the IFU. These are predom- function, which probes the redshift range mated star-formation rate corrected for inantly single line objects, and for 14 all of 2.3 < z < 4.6 extends the work of the nar- obscuration. With this correction in place the characteristics point to them being row-band searches to fainter luminosities it is apparent that our IFU search is in hydrogen Lyα emission-line galaxies (two where the luminosity function keeps line with previous studies conducted in a others are [O II] emitters and the third is the same Schechter function form over number of different ways. However, the the type-II quasar discussed later in this redshifts up to z ~ 6. This implies that benefit of using the integral-field approach article), we will now concentrate on these there is little evolution in the star-formation is that we select sources at all redshifts Lyα emitters. Lyα emission is produced rate density over this redshift range, al- in our volume in precisely the same way, by massive stars photoionsing hydrogen though small number statistics preclude thus reducing the biases involved in gas. By using some simple assumptions strong statements regarding any evolution. comparing studies at different redshifts it is possible to estimate the star-forma- from different surveys, which may utilise tion rate in galaxies which exhibit Lyα As stated above, knowledge of the lu- different techniques. emission by measuring the luminosity of minosity of the Lyα emission line in these the emission line. Although undoubtedly galaxies gives information on the total Further it is also worth mentioning that the crude, this does at least produce a lower star-formation rate. Using typical assump- choice of field, i.e. one containing a limit for the star-formation activity in dis- tions of hydrogen recombination the star- powerful radio galaxy at z = 2.92, does tant galaxies. If we now bin all of the Lyα formation rate is given by, not bias the results in any way. Our data luminosities in the volume then we are contains only one Lyα emitter at the –36 –1 able to construct the Lyα emitter luminos- SFR = 9.1 × 10 (L(Lyα) / W) Mीyear . redshift of the radio galaxy. This is princi- ity function, i.e. the number density of pally due to the small area probed by emitters at a given luminosity per unit vol- the IFU. However we can quantify how

The Messenger 121 – September 2005 39 Reports from Observers Javis M. J. et al., Surveying the High-Redshift Universe with the VIMOS IFU

many we would expect in our data at this to the nucleus is through the opening quasars. Using these line luminosities it is redshift, given the typical overdensities in the torus, and we see the unresolved possible to estimate the lower mass limit of emitters found in narrow-band search- nucleus and the high-velocity clouds of the accreting black hole in the centre of es around powerful radio galaxies. In their (v > 2 000 km/s) of gas which surround it. this galaxy. We assume the typical line study of Lyα emitters around the powerful Whereas for radio galaxies, the torus lies ratios of radio galaxies to convert the He II radio galaxy TN J1338-1942 at z = 4.1, along our line of sight obscuring our view luminosity to a line luminosity in [O II], Venemans et al. (2002) showed that the to the central engine, these are type-II which is correlated with the total bolomet- overdensity of emitters was a factor AGN and we only see the low-velocity, ric luminosity of the AGN. Under the as- of ~ 15 more than one would expect in a narrow forbidden (v < 2 000 km/s) emis- sumption that the quasar is accreting at blank-field search. Using this fact we sion lines. Moreover, there is also a pop- its maximum rate, i.e. the Eddington lim- would expect to find of order one object ulation of radio-quiet quasars which out- it, then this bolometric luminosity equates 8 within ∆ z = 0.004 of the radio galaxy. number their radio-loud counterparts by a to a black-hole mass of 3 × 10 Mी. In the IFU data cube we find one object at factor of ~ 10. These are relatively easy a distance of ∆ z = 0.002. Thus although to find due to the fact they exhibit a char- In the local Universe there is now a well- in agreement with the expected overden- acteristically very blue continuum and known correlation between the mass sity for a protocluster, the poor number appear as unresolved point sources in im- of black holes and the luminosity of their statistics arising from the relatively small aging surveys. By simple methodology host galaxy (see e.g. Magorrian et al. field-of-view of the IFU, precludes any there should also be a large population of 1998). The near-infrared K-band (2.2 µm) strong statement about the clustering of radio-quiet obscured AGN. This can magnitude of J0945-242 is very faint, Lyα emitters around the radio source. also be inferred from models of the X-ray with K = 20.5. Radio galaxies at z = 1.65 However, we do find what seems to be background, where the universal hard typically have host galaxy luminosities an excess of Lyα emitters at z ~ 2.5, X-ray emission cannot be accounted for of K ~ 18. Thus the host galaxy of J0945- where there are three emitters within unless there is a large population of ob- 242 appears to be 2.5 mag (or a factor ∆ z = 0.04 of each other. This leads us to scured AGN at high redshift. of 10) fainter than that for a typical radio- believe there may be a probable high- loud type-II AGN. If this faintness of the redshift cluster at this redshift, although These type-II AGNs are relatively difficult host galaxy is caused by extinction from there is no known powerful AGN in the to find compared to the type-I counter- dust then we would expect the blue vicinity. However, deep, wider-field obser- parts. This is principally due to the fact end of the galaxy spectrum to be fainter, vations are needed to confirm this. that type-II AGN look like normal galaxies, as dust attenuates the blue light more and it is only by looking for other signa- readily than at red wavelengths. However, tures of AGN activity, which do not suffer the host galaxy of J0945-242 is extremely Discovery of a type-II quasar from extinction due to the torus, they can blue, indicative of ongoing star formation. in the IFU deep field be found, e.g. X-rays from the central Therefore, the faintness in the K-band engine which penetrate the torus, radio light indicates that the host galaxy has a In this section we discuss the way in emission from powerful jets or repro- dearth of old, massive stars, which in which our integral-field data has also led cessed dust emission in the mid-infrared turn implies that the galaxy is not yet fully to the discovery of two Active Galactic from the torus itself. However, with the formed at z = 1.65. Whereas the black Nuclei (AGN) in the volume probed, in ad- integral-field approach we are sensitive to hole has already grown, presumably by dition to the radio galaxy which was tar- the bright narrow-emission lines that are accretion of matter, close to its final geted. One of these is a “normal” unob- characteristic of an obscured AGN, as we mass due to the fact that the low-redshift scured type-I quasar with broad emission obtain the spectrum of any object in the black-hole mass function shows that lines and an unresolved morphology IFU field immediately. supermassive black holes appear to have 10 on optical images at a redshift of z = 1.79. a maximum mass of around 10 Mी. However, the other AGN exhibits only nar- J094531-242831 (hereafter J0945-242) row-emission lines (Figure 4) and has a exhibits these bright narrow-emission This relatively large black-hole mass as- resolved morphology in the optical image. lines, in the C IV doublet (λλ = 154.8 nm, sociated with a host galaxy approximately 155.1 nm), He II (λ = 164.0 nm) and C III] a factor of 10 fainter than what would From radio surveys we know that there (λ = 190.9 nm), all characteristic of a type-II be expected from the local relation implies are at least two populations of power- AGN. The radio map shows that there that supermassive black holes at high ful radio-loud AGN, radio-loud quasars is no radio emission down to a radio flux redshift may essentially be fully grown be- (RLQs) and radio galaxies (RGs). Under limit of 0.15 mJy at 5 GHz. At a redshift fore the host galaxy has fully formed. the model for the unification of AGN, of z = 1.65 this is significantly below the This is in qualitative agreement with what this difference is dictated solely by the ori- typical luminosity of a radio galaxy, thus we already see in high-redshift radio gal- entation of the AGN with respect to we confirm that this is a genuine radio- axies, where the small, young, radio our line-of-sight, where the presence of a quiet type-II quasar. The line luminosity ra- sources appear to have extremely bright dusty torus surrounding an accreting tios of the C IV, He II and C III] lines are also sub-millimetre luminosities. This extreme- supermassive black hole may obscure our consistent with the ratios for radio galax- ly luminous sub-millimetre emission is due view to the nucleus. RLQs are the unob- ies, and not the generally lower-luminosity to reprocessed UV light from young scured type-I population where our view Seyfert-I galaxies and the unobscured stars which has been absorbed by the

40 The Messenger 121 – September 2005 Figure 2: The number density of Lyα emitters plotted Cowie and Hu 1998 against luminosity. The filled symbols mark surveys Kudritzki et al. 2000 with an average redshift similar to ours (triangles and Ajiki et al. 2003 circles) and the open symbols stand for surveys at Hu et al. 2004 redshift z = 5.7 (squares and inverted triangles). Over- This project plotted are two Schechter luminosity functions: the solid line is the fit to all our data points and the dashed line is the fit to our two highest luminosity data points and those of the surveys at similar redshift with L > 5 × 1035 W (dashed horizontal line) to ensure completeness. The dotted horizontal lines mark the detection limits of the surveys.

10 –1 1.0000 CH98 Aj03 Ku00 Hu04 L

K O

–2 ) 10 0.1000 H – M 3 Q ) I N W J X – C P 3 B

M F G – p 1 A M c

y V T r ी – 0.0100 p –3

1 D E 10 R Y c M S CC 0

. BB 7 ( h Φ

S Z F ρ ( R ∆ –4 0.0010

l 10 DD o AA U g L

0.0001 10 –5 0 2468 34.5 35.0 35.5 36.0 36.5 Redshift LogLLyα(W)

3.0 Figure 3 (above): Star-formation-rate densities as Hα emitters derived by various types of surveys. The result from O-lines this work is denoted by the filled star derived from Multi-colour J0945–2428 2.5 integrating over the luminosity function fit to our data Lyα emitters z = 1.65 alone. The different types of surveys are marked with This paper C IV He II different symbols: the open circles are Hα searches,

) the open triangles are surveys aimed at oxygen –

1 2.0 emission lines, the filled triangles are multicolour sur- Å veys, and the open squares are Lyα searches. – 2

C III]

W 1.5 m – 2 0 1.0

0.5 F l u x 0.0 d e

n Figure 4 (left): The 1-D spectrum of the type-II quasar, s

i J0945-2428 at z = 1.65. The spectrum was extracted t y –0.5 over the whole galaxy (seven IFU fibres). The shad- ( 1 4000 4500 5000 5500 6000 6500

0 ed regions show the wavelengths affected by sky-line Wavelength (Å) emission. large amounts of dust associated with currently the only instrument which has Full details of the work presented in this star-forming regions, and re-radiated the capability of large spectral coverage article can be found in van Breukelen, in the far-infrared. In order to produce coupled with a ~ 1 square arcminute Jarvis & Venemans (2005) and Jarvis, van these sub-millimetre luminosities, star-for- field-of-view. However, future instruments, Breukelen & Wilman (2005). –1 mation rates of up to 1000 Mीyr are such as the Multi-Unit Spectroscopic needed, typical of a galaxy undergoing its Explorer (MUSE; http://muse.univ-lyon1.fr), first major bout of star-formation activity. will expand the initial work taking place in References this field with VIMOS. Furthermore, vol- Ajiki M. et al. 2003, AJ 126, 2091 umetric surveys with IFUs may begin to Hu E. M., Cowie L. L., McMahon R. G., Capak P., Conclusions find types of objects we have yet to dis- Iwamuro F., Kneib, J.-P., Maihara T., Motohara K. cover in traditional surveys, and thus offer 2002, ApJ 568, 75 The new method of detecting emission- a whole new view of the Universe. Jarvis M. J., van Breukelen C., Wilman R. J. 2005, MNRAS 358, 11 line galaxies at high redshift along with the Magorrian J. et al. 1998, AJ 115, 2285 serendipitous discovery of an obscured Steidel C. C., Adelberger K. L., Shapley A. E., Pettini quasar at z = 1.65, highlights the way M., Dickinson M., Giavalisco M. 2000, ApJ 532, in which relatively wide-area integral-field 170 van Breukelen C., Jarvis M. J., Venemans B. P. 2005, units on large telescopes can open up a MNRAS 359, 895 unique window on the Universe. VIMOS is Venemans B. P. et al. 2002, ApJ 569, 11

The Messenger 121 – September 2005 41 Reports from Observers

The zCOSMOS Redshift Survey

Simon Lilly (ETH, Zürich, Switzerland) that have been developed, using almost are the product of the gravitational growth and the zCOSMOS team* all of the most powerful observing facil- of initially tiny density fluctuations in the ities in the world. This next step is called distribution of dark matter in the Universe COSMOS and the ESO VLT will make a – fluctuations which likely arise from quan- The last ten years have seen the open- major enabling contribution to this pro- tum processes in the earliest moments ing up of dramatic new vistas of the fur- gramme through the zCOSMOS survey of the Big Bang, τ ~10–35 s. These densi- thest reaches of space and time – an being carried out with the VIMOS spec- ty fluctuations eventually collapse to make exploration in which the VLT has played trograph. gravitationally-bound dark matter struc- a major role. However, the work so far tures within which the baryonic material has been exploratory, and sampled only cools, concentrating at the bottom of the small and possibly unrepresentative vol- It is well known that the finite speed gravitational potential wells where it forms umes of the distant Universe. The next of light enables us to observe very distant the visible components of galaxies. step is to bring to bear on a single large objects as they were when the Universe area of sky the full range of techniques as a whole was much younger, and there- In many respects, the Λ-CDM paradigm by to directly observe the evolving prop- is strikingly successful, especially in de- erties of the galaxy population over cos- scribing large-scale structure. On galactic mic epoch. The most distant objects scales, current implementations of it face * Peter Capak2, Marcella Carollo1, Andrea Cimatti 3, Thierry Contini4, Emanuele Daddi 5, Luigi Guzzo 6, presently known lie at redshifts between some difficulties: for example, real galax- Gunther Hasinger 7, Jean-Paul Kneib8, Olivier six and seven (6 < z < 7) corresponding ies appear to have more angular momen- Le Fevre8, Steve Maddox 9, Henry McCracken10, to a “look-back” time of about 95 % of the tum than predicted in numerical Λ-CDM 11 12 Alvio Renzini , Marco Scodeggio , Gianni age of the Universe. Indeed, at the time simulations and the down-sizing trend Zamorani13, Stephane Arnouts8, Sandro Bardelli13, Micol Bolzonella13, Dario Bottini12, Angela that these objects emitted the light that we is in a sense opposite to that expected. Bongiorno13, Alberto Cappi13, Olga Cucciati12, now detect, the Universe was less than There is also no clear understanding Sebastien Foucaud9, Olivier Ilbert13, Angela Iovino12, one billion years old. of the links between galaxies and their 1 4 4 Pawel Kampczyk , Fabrice Lamareille , Roser Pello , nuclear supermassive black holes. These Vincent Le Brun8, Alexi Leauthaud8, Christian Maier1, Vincenzo Mainieri7, Christian Marinoni12, These observations have revealed a rich various shortcomings almost certain- Marco Mignoli13, Elena Ricciarelli13, Claudia phenomenology in the early Universe. ly reflect our poor understanding of how Scarlata1, John Silverman7, Lidia Tasca 8, Laurence As we look back in time, we see that the dark matter and baryons interact, of 8 12 13 Tresse , Daniela Vergani , Elena Zucca , Herve global star-formation rate was about the feed-back loops operating within the Aussel10, Marcella Brusa7, Alberto Franceschini 14, Paolo Franzetti12, Bianca Garilli12, Gianni Marconi 11, a factor of ten or more higher in the first baryonic material due to energy injection Baptiste Meneux8, Bahram Mobasher15, John third of the history of the Universe (at from star formation and active galac- Peacock16, David Sanders17, Roberto Scaramella18, z > 1) than it is now. It is clear that the tic nuclei and of the relative importance 19 20 Eva Schinnerer , David Schiminovich , Nicholas most violent star-bursting objects are en- in galaxies of internal dynamical evolu- Scoville 2, David Silva11, Ian Smail 21, Dario Maccagni12, Yoshi Taniguchi 22, Paolo Vettolani13, shrouded in dust and will make production and externally driven events such as and Alessandra Zanichelli13. tive targets of study in the future with mergers, in redistributing material within ALMA. Alongside these very active galax- them. Many of these current uncertainties 1 ETH Zürich, Switzerland ies, there are also examples of more are likely related to the environments 2 California Institute of Technology, Pasadena, USA 3 INAF – Osservatorio Astrofisico di Arcetri, Flo- passive galaxies which must have com- that a forming and evolving galaxy finds rence, Italy pleted their star formation quite early itself in. Except for the very richest en- 4 Laboratoire d’Astrophysique de l’Observatorie on. Consistent with our knowledge of the vironments (i.e. the rich clusters of galax- Midi-Pyrénées, Toulouse stellar content of galaxies today, we see ies), knowledge of the environments of 5 National Optical Astronomy Observatories, Tuc- son, USA in the high redshift Universe that high lev- distant galaxies is rather poor. One of the 6 Osservatorio di Brera, Milan, Italy els of star formation, and other signatures aims of zCOSMOS is to characterise 7 Max-Planck-Institut für Extraterrestrische Physik, of youthfulness, appear in progressive- these environments over a wide range of Garching, Germany ly more massive galaxies as we look back redshifts and thus to lead to a much bet- 8 Laboratoire d’Astrophysique de Marseille, France 9 Nottingham University, United Kingdom further in time, a phenomenon given the ter physical understanding of the forces 10 Institut d’Astrophysique de Paris, France rather confusing name of “down-sizing”. controlling the formation and evolution of 11 ESO galaxies through cosmic time. 12 CNR Istituto di Astrofisica Spaziale e In parallel, developments in cosmology Fisica Cosmica Milano, Italy 13 INAF – Osservatorio di Bologna, Italy and in particular the emergence of the Much of the progress in this field has 14 Università di Padova, Italy “concordance cosmology” (from observa- been driven by “Legacy” style pro- 15 Space Telescope Science Institute, Baltimore, tions of the microwave background, large- grammes, such as the Hubble Deep Fields Maryland scale structure in the present-day Uni- (HDF), and the GOODS project, in which 16 University of Edinburgh, United Kingdom 17 University of Hawaii, Honololu, USA verse and the Hubble diagram of distant the data have been archived and released 18 INAF Roma, Italy Type 1a supernovae) have given us for to the research community in a scienti- 19 Max-Planck-Institut für Astronomie, Heidelberg, the first time a theoretical paradigm for fically usable form. This allows a much Germany the formation of galaxies and other, larger larger community of astronomers, extend- 20 Columbia University, New York, USA 21 Durham University, United Kingdom scale, structures in the Universe – the ing well beyond the original team who 22 Tohoku University, Tokyo, Japan Λ-CDM model: Structures in the Universe acquire and first analyse the data, to use

42 The Messenger 121 – September 2005 the data to carry out their own research programmes. COSMOS and zCOSMOS 24.0 23.5 23.0 22.5 22.0 21.5 21.0 20.5 20.0 are both undertaken in this spirit, and the purpose of this Messenger article is to bring to the attention of potential users across the ESO community the features of the zCOSMOS programme, which has just started on the VLT in P75. GOODS

The global COSMOS project

The Cosmic Evolution Survey (COSMOS) was designed to bring to bear on a single very large field all of the tools and observational techniques that have been developed for the study of the distant Uni- verse. The COSMOS field (centred on HDFs 10 h 00m 29s +02° 12o 21ǥ) was chosen to be near the Celestial Equator so that it can be accessed from observatories in both hemispheres, e.g. the ESO VLT and ALMA as well as the large optical/infrared telescopes in Hawaii and Chile and the VLA radio telescope in New Mexico, USA.

The COSMOS project is built around a mosaic of 600 images taken with the Ad- 1.0 f 814–f 475 2.4 vanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST). The Figure 1: The 1.7 deg2 COSMOS field compared with mosaic covers a contiguous area of large-scale structure in a ∆ z = 0.02 slice of the Uni- 2 verse at z ~ 1 (courtesy Andrew Benson). Dots repre- 1.7 deg and represents the largest single sent galaxies, colour-coded according to their ob- programme undertaken with the HST to served colour (lower scale) and by size according to date. The field spans a transverse dimen- apparent magnitude (upper scale). The distribution sion of 80 comoving Mpc at z ~ 1 and of galaxies in the cosmic web of filaments and voids is clearly seen. By comparison the much smaller fields 160 comoving Mpc at z ~ 3 and covers a of view of the HDFs and the GOODS surveys (on the 3 volume to z ~ 3 (about 50 million Mpc ) right) do not well sample the range of structures that is approaching that of the entire local and environments that are present in the Universe at Sloan Digital Sky Survey at redshifts any epoch. z < 0.1. The HST observations were completed in June 2005. Despite being only ages from the CFHT and NOAO 4-m and near-infrared (150 nm – 8 µm) wave- single-orbit exposures, the broad F814W telescopes. The combined photometric bands. filter reaches to within 0.3 magnitudes catalogue contains well over 1 million of the well-known GOODS images even galaxies with photometrically estimated Deep imaging observations at other though the survey covers an area twenty redshifts and approximate spectral types. wavelengths, e.g. the X-ray and radio, re- times larger than the combined GOODS-N The field has also been observed with the veal the signatures of accretion onto and GOODS-S fields (see Figure 1). GALEX ultraviolet satellite to a depth black holes in active galactic nuclei (AGN) of AB ~ 26 at 150 and 225 nm. Observing and of energetic bursts of star formation Impressive as the HST images are, the time on the Spitzer observatory has been that are obscured by dust. A mosaic of real power of COSMOS stems from awarded to extend this photometric cov- deep X-ray images obtained with the ESA the addition of a wealth of other observa- erage into the mid-infrared 3–8 µm which XMM-Newton satellite have already yield- tions that are being amassed on this will substantially improve the photometric ed more than 1000 active galactic nuclei field by the truly global COSMOS consor- redshifts and the estimates of the stel- and about 100 X-ray selected groups tium. Most notably, the SuprimeCam on lar masses of the galaxies. Ultimately, we and clusters of galaxies, while deep VLA the Subaru 8-m has been used to ob- hope to have photometry and images images at 1.4 GHz reaching to about tain very deep BGVRIZ images of the from a suite of almost 30 intermediate- 50 µJy (5σ) will detect 4 000 radio sources. whole field with a limiting magnitude (5σ) and broad-band filters spanning the full Future observations planned at far-infra- of about AB ~ 26–27. These have been range of starlight in the ultraviolet, optical red and sub-millimetre wavelengths will supplemented by U-band and K-band im- complete the observational picture.

The Messenger 121 – September 2005 43 Reports from Observers Lilly S. et al., The zCOSMOS Redshift Survey

What distinguishes COSMOS from pre- Table1: Numbers of representative objects in the COSMOS survey. vious programmes such as the Hubble Deep Fields, GOODS and COMBO- COSMOS Inventory 17/GEMS, is its enormous area. This Category Selection Number Faint galaxies I < 27 1 million gives us: AB X-ray selected AGN I < 27 3 400 – unprecedentedly large samples of AB X-ray selected clusters S > 5 10 –16 c.g.s. 10 0 objects in the distant Universe, thereby X × Radio sources S > 50 µJy 4 000 ensuring statistical weight even for rare 1.4 classes of objects (see Table 1); Bright quasars B < 21 10 0 High z quarsars (z > 4) I < 25 50 – confidence that we are sampling truly AB representative volumes of the Universe ULIRGS … 3 000 Lyman break galaxies I < 25.5 10 000 at high redshift (mitigating the so- AB Passive galaxies (z ~ 3) K < 24 10 000 called cosmic variance problem asso- AB zCOSMOS 0.3 < z <1.2 I < 22.5 25 000 ciated with smaller surveys that effec- AB galaxies with redshift tively probe a one-dimensional beam zCOSMOS 1.3 < z < 2.5 BAB < 25 12 500 through the Universe); galaxies with redshift – the ability to place all objects in their environment, from small scale groups of galaxies up to the largest structures in the Universe.

Such a unique data set of course opens tra themselves yield important diagnostics requirements efficiently, the zCOSMOS other equally unique possibilities. For in- of the evolutionary state of individual programme is split into two components, stance, the HST images will allow the galaxies, including measures of the star- each requiring different VIMOS configura- distribution of dark matter to be mapped formation rate, dust extinction, the gas tions and exposure times. 13 down to structures of order 3 × 10 Mी, and stellar metallicities, and stellar popu- which may be compared with the distribu- lation parameters such as ages. The The “bright” sample of 25 000 COSMOS tion of luminous galaxies. In addition, the spectra can confirm the identifications of galaxies is selected to have IAB < 22.5. large number of quasars bright enough radio and X-ray sources through the The straight I-band selection yields for absorption line spectroscopy (Table 1) characteristic signatures of AGN or star- a sample of galaxies at 0.2 < z < 1.2, will enable us to map the distribution burst activity. Precise spectroscopic red- reaching 1.5 mag below L* at z ~ 0.7 of neutral gas in the intergalactic medium shifts can of course also be used to where it corresponds to selection in the and again, compare that with the large- improve and characterise the photometric rest-frame V-band. With a sampling scale structure defined by the galaxies. redshift schemes which can then be ap- rate of at least 70 % and a velocity accu- plied to every galaxy in the field. racy of at least 100 kms–1, enabling the 12.5 isolation of groups down to 3 × 10 Mी, The zCOSMOS redshift survey The VIMOS instrument on the VLT pro- the “bright” sample is designed to be vides ESO with a unique capability directly comparable to the very large zero- The COSMOS data sets mentioned above for undertaking such a survey and in P75 redshift samples (SDSS and 2dfGRS) consist of exquisite two-dimensional a Large Programme was awarded but at a look-back time of half the age of images of the sky at almost every imagi- 540 hours of observation time to carry out the Universe. The input target list is gene- nable wavelength. The crucial third the zCOSMOS redshift survey. This rated from the HST/ACS images. The dimension is added by knowledge of the programme is complementary to the other observations are made with the VIMOS redshifts of the sources. Some informa- large VIMOS programme, the VVDS MR grism in 1 hr exposures between tion on the redshifts may be derived from Survey carried out by the VIMOS Instru- 550 < λ < 960 nm at resolution R ~ 600. the broad-band colours of the objects, ment Team. About 160 galaxies can be observed so-called “photometric redshifts”, but the simultaneously. Successive VIMOS point- more secure and precise “spectroscopic The design of the zCOSMOS programme ings are stepped in Right Ascension redshifts” are required for many purposes: has been driven primarily by the desire to and Declination so that every galaxy in the The increased precision relative to the quantify the environments of galaxies and target sample has eight opportunities to best attainable photometric redshifts ena- AGN over a broad range of epochs. This be selected into a spectroscopic mask, bles the delineation of the cosmic web requires: A high sampling completeness ensuring a uniform statistical sampling a- of large-scale structure in the Universe, (~ 70 % of objects observed from a given cross the field without significant biases from small groups of galaxies up to the target sample); uniform sampling cover- against near neighbours, etc. largest filaments and voids. The measure- age across the whole field; a broadly con- ment of individual velocities of galaxies tiguous redshift coverage from very The extension to higher redshifts requires enables dynamical studies of these struc- low redshifts to redshifts z > 2.5 spanning a different strategy. We know from the tures, yielding masses, dynamical states 80 % of cosmic time; relatively high veloc- VVDS survey that simply selecting fainter and cosmological information. The spec- ity accuracy (100 kms–1). To achieve these galaxies results in a sample that is still

44 The Messenger 121 – September 2005 dominated by relatively low redshift galax- and the LR-Blue grism (370 < λ < 670 nm zCOSMOS schedule and ies, with only a small “tail” at higher red- at R ~ 200) should yield redshifts in data release plans shifts 1.5 < z < 4 emerging faintwards of 4.5 hr exposures for 12 500 such galax- AB ~ 23.5. In order to isolate this tail, the ies, with a similar sampling rate as for Execution of a programme of the size of zCOSMOS “faint” sample of 12 500 gal- the bright sample, and a velocity accuracy zCOSMOS on a single field places unique axies is selected using a combination of 300 kms–1. demands on ESO in the scheduling of the of proven colour-colour selection criteria, VLT: to be completed in a timely manner, specifically the (B-Z)/(Z-K) selection In both parts of the survey, radio source the UT3 must be used for this programme proven by the VLT K20 survey and a de- and X-ray source candidate identifications for essentially all the time that the field is velopment of the (U-G)/(G-R) selection are added to the masks either as random observable. Periodic data releases will be used by Charles Steidel and collaborators targets (which will be observed with made with a final comprehensive data set to isolate star-forming galaxies. These a roughly 70 % sampling rate) or, for high placed in the ESO Archive shortly follow- two selection criteria yield a sample of priority and urgently needed sources, as ing completion of the programme, thereby galaxies at 1.2 < z < 2.4 and BAB < 25.0. compulsory targets which are observed providing the general research community In order to keep the total programme size with close to 100 % efficiency early in the with a detailed census and sample of the manageable, the higher redshift part of programme. distant Universe. zCOSMOS is limited to the central 1 deg2 area, which nevertheless still yields a URL references comparable comoving transverse dimension to that of the lower redshift com- http://www.astro.caltech.edu/~cosmos ponent. A four-pass strategy with VIMOS http://www.exp-astro.phys.ethz.ch/zCOSMOS

Figure 2: Simulation of the final zCOSMOS redshift survey showing the spatial distribution (in comoving space) of objects in the survey over the redshift interval 0 < z < 2.4, in which every dot represents a zCOSMOS galaxy with spectroscopically determined redshift. The red bars mark increments of 0.1 in redshift z. The figure has been generated from the COSMOS mock catalogues produced from the Mil- lennium Run cosmological simulation (courtesy of Manfred Kitzbichler).

The Messenger 121 – September 2005 45 Reports from Observers

Observing with the New High-Speed Camera ULTRACAM on Melipal

British astronomers1 have opened a new window on the Universe with the recent commissioning of the Visitor Instru- ment ULTRACAM on the VLT).

ULTRACAM is an ultrafast camera capable of capturing some of the most rapid astronomical events. It can take up to 500 pictures a second in three different colours simultaneously. It has been designed and built by scientists from the Universities of Sheffield and Warwick (United Kingdom), in collaboration with the UK Astronomy Technology Centre in Edinburgh.

ULTRACAM employs the latest in charged coupled device (CCD) detector technology in order to take, store and analyse data at the required sensitivities and speeds. CCD detectors can be found in digital cameras and camcorders, but the devices used in ULTRACAM are special because they are larger, faster and most important- ly, much more sensitive to light than the Figure 1: The ULTRA- detectors used in today’s consumer elec- CAM instrument mounted on the visitor focus of tronics products. Melipal (UT3).

In May 2002, the instrument saw “first light” on the 4.2-m William Herschel Tele- (UK) and the ULTRACAM project scien- One of the faint objects studied with scope (WHT) on La Palma. Since then tist. “Using ULTRACAM in conjunction ULTRACAM on the VLT is GU Muscae. the instrument has been awarded a total with the current generation of large tele- This object consists of a black hole in of 75 nights of time on the WHT to study scopes makes it now possible to study a 10-hour orbit with a normal, solar-like any object in the Universe which eclipses, high-speed celestial phenomena such as star. The black hole is surrounded by a transits, occults, flickers, flares, pulsates, eclipses, oscillations and occultations in disc of material transferred from the nor- oscillates, outbursts or explodes. These stars which are millions of times too faint mal star. As this material falls onto the observations have produced a bonanza of to see with the unaided eye.” black hole, energy is released, producing new and exciting results, leading to eleven large-amplitude flares visible in the light scientific publications already published or The instrument saw first light on the VLT curve. This object has magnitude 21.4, in press. on May 4, 2005, and was then used for that is, it is one million times fainter than 17 consecutive nights on the telescope to what can be seen with the unaided eye. To study the very faintest stars at the very study extrasolar planets, black-hole bi- Yet, to study it in detail and detect the highest speeds, however, it is necessary nary systems, pulsars, white dwarfs, as- shortest possible pulses, it is necessary to use the largest telescopes. Thus, work teroseismology, cataclysmic variables, to use exposure times as short as 5 sec- began two years ago preparing ULTRA- brown dwarfs, gamma-ray bursts, active onds. This is possible with the large aper- CAM for use on the VLT. galactic nuclei and Kuiper-belt objects. ture and great efficiency of the VLT.

“Astronomers using the VLT now have an These unique observations have revealed instrument specifically designed for the a series of sharp spikes, separated by study of high-speed phenomena”, said approximately seven minutes. Such a sta- Vik Dhillon, from the University of Sheffield ble signal must be tied to a relatively stable structure in the disc of matter surrounding the black hole. The astrono- 1 The ULTRACAM team is composed of Vik Dhillon, Stuart Littlefair, and Paul Kerry (Sheffield, UK), Tom mers are now in the process of analysing Marsh (Warwick, UK), Andy Vick and Dave Atkinson these results in great details in order (UKATC, Edinburgh, UK). For the installation on to understand the origin of this structure. the VLT, they received support from Kieran O’Brien and Pascal Robert (ESO, Chile). The ULTRACAM project page can be found at http://www.shef.ac.uk/ ~phys/people/vdhillon/ultracam

46 The Messenger 121 – September 2005 0 0 6

Another series of observations were dedi- Figure 2: First light with ULTRACAM on cated to the study of extrasolar planets, the VLT: The field of the transiting extra- solar planet OGLE-TR-56b. The image 0 more particularly those that transit in front 0 shows only a portion of one of the three of their host star. ULTRACAM observations 4 ULTRACAM CCD chips. Thousands

s of such one-second images were ob-

have allowed the astronomers to ob- l

e tained in order to derive an accurate x tain simultaneous light curves, in several i

p light curve of the transit at three differ- colour-bands, of four known transiting Y ent wavelengths, thereby enabling

exoplanets discovered by the OGLE sur- 0 an accurate determination of the radius 0 of the planet. vey, and this with a precision of a tenth 2 of a per cent and with a one-second time resolution. This is a factor ten better than previous measurements and will provide very accurate masses and radii for 200400600 800 1000 X pixels these so-called “hot-Jupiters”. Because ULTRACAM makes observations in three different wavebands, such observations will also allow astronomers to establish whether the radius of the exoplanet is different at different wavelengths. 5

This could provide crucial information on . the possible exoplanets’ atmosphere. 2

The camera is the first instrument to make GU Mus, 09 May 2005 Figure 3: Light curves of the black hole use of the Visitor Focus on Melipal (UT3), GU Muscae. This figure shows an early

2 scientific highlight from the first few and the first UK-built instrument to be nights of the ULTRACAM observing mounted at the VLT. The Visitor Focus al- campaign on the VLT: light curves in the lows innovative technologies and instru- I- (red) and G-band (green) of the mentation to be added to the telescope quiescent black hole X-ray transient 5

. GU Muscae. This object consists of a for short periods of time, permitting 1 black hole in a 10-hour orbit with a x u studies to take place that are not available l normal solar-like star. The black hole is with the current suite of instruments. F surrounded by an accretion disc of material transferred from the solar-like

1 star. As this material accretes onto “These few nights with ULTRACAM on the the black hole, energy is released, and VLT have demonstrated the unique dis- this is evident from the large-amplitude coveries that can be made by combin- flares visible in the light curves. ing an innovative technology with one of What was not expected, however, is

5 the series of sharp spikes that can be .

the best astronomical facilities in the 0 10 10.1 10.2 seen, and which are separated by ap- world”, said Tom Marsh of the University MJD – 53490 (day) proximately seven minutes. Such a of Warwick and member of the team. stable signal must be tied to a relatively “We hope that ULTRACAM will now be- stable structure in the accretion disc. come a regular visitor at the VLT, giving European astronomers access to a unique new tool with which to study the Universe.”

The next run with ULTRACAM on the VLT is currently scheduled for November 2005, and plans are under way for a third Figure 4: The ULTRACAM commission- run sometime during 2006. Anyone inter- ing team in the VLT control room at first light. From left to right: Pascal ested in applying for time on the instru- Robert (ESO), Ariel Lopez (ESO), Kieran ment should contact one of the authors in O’Brien (ESO), Andy Vick (UKATC), the first instance. (Any such observations David Atkinson (UKATC), Paul Kerry also require the approval of the OPC.) (Sheffield), Vik Dhillon (Sheffield), Stuart Littlefair (Sheffield), Andreas Kaufer (ESO), Tom Marsh (Warwick). (Based on ESO Press Release 17/05)

The Messenger 121 – September 2005 47 Telescopes and Instrumentation

ALMA News

Tom Wilson (ESO) calorimeter systems and the precision On July 6 and 7, 2005 the FE IPT sucess- muon spectrometer. Since 1989 he has fully completed its delta Preliminary held a position as Scientific Associate Design Review (PDR). The review meeting Antenna procurement at the Laboratory for High Energy Physics was held at ESO Headquarters in of the Eidgenössische Technische Hoch- Garching, Germany. The review panel, The antennas are the largest single item schule (ETH) in Zürich. He was intensively chaired by the European ALMA System in the ALMA budget. Thus the status involved in many scientific and managerial Engineering & Integration IPT Lead, of antenna procurement is of the highest issues concerning the L* Experiment at Christoph Haupt, consisted of experts importance for the project. Associated the Superconducting Super Collider, SSC, both internal to the project as well as Universities Inc/NRAO have been given and the proposed Lepton-Photon-Pre- noted receiver experts from Australia and ALMA Board approval and permission by cision-Physics (L3P) Experiment for the the USA. Based on documentation made the US National Science Foundation to Large Hadron Collider, LHC, at CERN. available in preparation of the meeting procure their antennas. On July 11, they Since the beginning of 1994, he took over and the presentations at the meeting the signed a contract with VertexRSI for up important scientific, organisational and review panel came to a unanimous de- to 32 antennas for ALMA. ESO is moving financial responsibilities for the Compact cision that the Front End design was well ahead with its antenna procurement Muon Solenoid (CMS) experiment. He beyond the PDR status. The reviewers as quickly as possible. The Joint ALMA was engaged in many areas of the con- also provided valuable constructive criti- Office is leading the rebaselining (a re- struction of the lead tungstate crystal cism that will be taken into account in assessment of project costs). This is pro- detector and was deeply involved in the finalising the ALMA receiver design. The ceeding at full speed. There will be dis- organisation of the construction of the success of this design review was very cussions of both the rebaselining and CMS Magnet. much due to the joint efforts made by the antenna procurement issues at the next FE IPT sub-system engineers, Hans meetings of the ESO Council to be held Hans Rykaczewski joined ESO in July Rudolf (ESO) and Kamaljeet Saini (NRAO), in September. 2005 and is very much looking forward to and the support they received from others helping in making ALMA a success, in within the FE IPT. fruitful collaboration with the international partners in this project. That the ALMA FE IPT makes progress is also shown in a more tangible manner in that important assemblies are nearing the Progress for the ALMA Front Ends completion of their construction. At IRAM in Grenoble, France, the first pre-produc- The most important factors that deter- tion unit of the Band 7 Cartridge, covering mine ALMA sensitivity are the transmission the frequency range from 275 GHz to of the astronomical signals through the 373 GHz, is currently undergoing exten- earth’s atmosphere, the effective collect- sive testing to both verify the design and ing area, and the quality of the first stage this first unit itself. Noise measurements of the receivers, that is, the Front Ends. on the completed unit, using the first local The quality of Front Ends depends on oscillator delivered by NRAO, show ex- their stability and noise temperature. That ceptionally good performance. The results is, they should not introduce any system- are much better than the requirements atic errors, and should add the smallest (see graph). possible amount of noise. The ALMA Front Ends show noise temperatures that The first Band 9 pre-production cartridge, New European Project Manager are 3 to 5 times the limit determined covering the frequency range from by quantum mechanics. In recent months 610 GHz to 720 GHz, has also been Hans Rykaczewski is the new European the ALMA Front End Integrated Project copleted (see picture) and is undergoing ALMA Project Manager and Head of the Team (IPT) has shown several important extensive testing at NOVA/SRON in ESO ALMA Division. He studied physics signs of concrete progress towards Groningen, The Netherlands. Following in Aachen. He completed a doctoral the- the construction of receivers for the ALMA the Front Ends, one must have Intermedi- sis on searches for new quark flavours project. ate Frequency amplifiers to increase the at the Deutsches Elektronen Synchrotron power to the desired value. These IF am- DESY in Hamburg. In 1984, he moved plifiers must also have low noise and high to M.I.T. and was delegated to CERN for stability. The present tests are being done working on the design and construction with IF amplifiers having a bandwidth of of the L3 detector which was installed 4 to 8 GHz. The final IF amplifiers will cov- and taking data at CERN’s Large Electron er the required band from 4 to 12 GHz. Positron Collider, LEP. There he was re- These were recently delivered by Yebes sponsible for the timely fabrication of sev- Observatory in Spain and will be mounted eral subdetector elements, like magnet, in the Band 9 cartridge shortly.

48 The Messenger 121 – September 2005 ALMA receiver cartridges.

Cartridge 1 Trec Measurements

Trec (K) 200

180

160

140

120

100

In summary it can be stated that the re- 60 ceiver noise temperatures achieved on 40 the Band 7 and 9 cartridges are likely the best in the world over these wide fre- 20 quency bands in the sub-millimetre range. 0 Until recently the standard practice was 280 290 300 310 320 330 340 350 360 370 to use mechanical tuners in the receivers Frequency (GHz) to obtain the optimum noise perform- USB 454/HDL 10 ance. The quality of the ALMA Band 7 LSB 454/HDL 10 and 9 receivers become even more re- USB 454/Cartrige 1 LSB 454/Cartrige 1 markable when one takes into account ALMA Limit that both Band 7 and 9 receivers use no LSB – 454-less LO Power USB – Less LO Power mechanical tuning. The combination of modern, state-of-the-art design technology, well-equipped laboratories and last, but definitely not least, very skilled and dedicated staff at both IRAM and NOVA/SRON have been crucial for this success. (Contributed by Gie Han Tan, see also Tan et al. 2004, The Messenger 118, 18.)

Construction progress

The excavations for the Operations Sup- port Facility (OSF) buildings are now pro- gressing very well. The two levels of the future building are now clearly discernible. In addition, construction of the road between the OSF and the Array Operations Site at 5 000 m has moved up to the higher and more difficult part of the road at an altitude of 4 000 m. (Photo credits: Jörg Eschwey, see also his article next page.)

The Messenger 121 – September 2005 49 Telescopes and Instrumentation

ALMA Site Development

Jörg Eschwey (ESO) under a blanket of the most magnificent state-of-the-art treatment facilities. Each starry display only the Atacama can offer. day the cleaning staff removes the dust In the middle of this splendid scenery, of the ever-encroaching desert from inside In the remote Atacama Desert, some the development of the site for the ALMA and outside the habitat of the staff. 30 km South of the budding tourist hub of project has been carried out since its Visitors are impressed by the community San Pedro de Atacama, the next giant beginnings in respectful concordance with spirit as passers by greet them with leap for the world’s astronomical commu- the Chilean environmental law and with warmth and friendliness. When all come nity is under way. Nestled at approxi- the firm priority of maintaining friendly re- together in the dining room at meal times, mately 2 900 metres above sea level amid lations with the local communities of there is the true sense of everyone work- the rolling foothills of the Andean Plateau San Pedro and Toconao, our neighbours. ing as an enthusiastic team. the facility for the OSF (Operation Support Facility) base camp is complete, and we This true commitment to environmental To find an international group of Euro- are overseeing the initial earthwork for the and cultural preservation is clear as one pean, North American, Japanese and Technical Area Buildings. explores the access road branching Chilean professionals and workers collab- from the Chilean Highway 23 that climbs orating on the project, is truly inspiring. Overlooking the vast expanse of the Salar toward the camp. The road meanders de Atacama salt flats, the ALMA offices, its way past fields of cacti, some over Although much of the ALMA Camp con- dormitories and dining hall are an ap- 300 years old and reaching over 5 metres struction is finished, 15 new dormitories propriate reflection of the efficiency and in height, historical sites of primitive will soon be added. The office building will resilience of the surrounding desert life. hunter-gatherers, vicuñas, llamas and be fitted with a number of cubicle-style Fully equipped with all the amenities such other wild life. The surrounding mountains office spaces, a recreational facility will be as modern communication systems, (reaching as high as 6 000 metres) include constructed, and the dining room will be high-speed internet and e-mail, satellite active, dormant and extinct volcanoes. extended to welcome and accommodate TV, ecological waste water treatment, incoming European, North American, heating and air conditioning systems and Equipped with supplemental oxygen and Japanese and Chilean staff. excellent catering services, the camp is two-way radio contact staff and visitors a self-contained kernel of the 21st century negotiate their way along some 28 km of The construction of the permanent Tech- amid the harsh desert terrain. gravel road below rounded peaks pep- nical Facilities and the completion of the pered with abandoned sulfur mines to the Contractors Camp at the OSF are cur- A cheerful and fastidious staff maintain the foot of Cerro Chajnantor. Here we find the rently being tendered. Construction start more than comfortable dormitories, pre- site of the APEX and the Japan ASTE is scheduled for January 2006 and Sep- pare three meals daily with surprising vari- radio telescopes and within the location of tember 2005 respectively. ety, and enjoy an occasional barbecue the ALMA project, a marked field where at the camp’s very own outdoor barbecue 64 radio telescopes will come together to Construction of the foundation and super- hut. form the world’s largest radio telescope structure of the Technical Building at array. the Chajnantor site at an elevation of ap- Throughout the day, there are the sounds proximately 5 000 metres above sea of crews hard at work excavating, crush- Back at the OSF, there are no overhead level is scheduled to start in September– ing and filling and leveling the desert’s soil lines disturbing the views to earth and sky October 2005 and the rough finish of the to create the foundation base of the as all technical installations are kept un- access road will be completed by the end OSF Technical buildings. As the sun sets, derground. Waste water and effluents are of this year. impenetrable silence shrouds the camp treated biologically and with the use of ) 4 ( O S E , r e y e H . H . H : s o t o h P

Above: Work at the Operational Support Facility (OSF). Right: The APEX telescope at Chajnantor.

50 The Messenger 121 – September 2005

Telescopes and Instrumentation

Technology Transfer at ESO

Martin Cullum (ESO) was generated by SMEs, and this figure is Although ESO has no official mandate even larger now. This compares to only or funds to invest in Technology Transfer 45 % in the USA, for example. In general, activities, it is a clear goal in the charter Technology Transfer has become an larger enterprises have their own research of EIROforum1 of which ESO is a member. important theme for the European departments and development laborato- Through the very nature of its activities, Commission as a means of promoting ries, and the research carried out is large- ESO makes a significant contribution to innovation and competitiveness within ly, although by no means entirely, oriented Technology Transfer within the Member European industry. It is also an area towards specific products and fields that States. To help quantify this contribution where organisations like ESO, that are the company exploits commercially. This and to highlight the process at ESO, engaged in developing highly advanced is often referred to as the “closed” model a survey of ESO Technology was carried research facilities, can and do make for technological innovation. out in 2004 and the results presented to significant contributions. This article dis- the ESO Council in December 2004. The cussed some of the processes involved But even in the USA, SMEs invest three results are accessible from the main ESO in Technology Transfer and provides to six times more in R&D than their Euro- web page under Projects & Developments several examples of technological inno- pean counterparts who have traditionally and provide a compendium of technolo- vations developed by ESO in-house and relied more on “open” collaborations with gies that have been developed or promot- through its procurement activities. external academic and research organi- ed by ESO over the last 15 years or so. sations. This can have certain advantages Most of the examples are associated with in that the accessible areas of research the VLT development period. Broadly defined, Technology Transfer con- are very broad but experience has shown cerns the transfer of knowledge and in- that the transfer of innovations from novations from laboratories and research academia to industry is not a very efficient Processes of transferring technology institutes to industry, or the use of ideas process. Not infrequently, promising open at ESO and developments from one field in others collaborations fail due to problems relat- that were not originally intended. ing to the protection of Intellectual Proper- The transfer of ESO developed or pro- ty Rights that do not exist with in-house moted technologies to industry can take At its meeting in Lisbon in 2000, the Euro- developments. several forms. pean Council set the objective of trans- 1. Novel technologies that have been de- forming the EU into the “most competitive Apart from targeted research collabora- veloped by ESO or pushed beyond and dynamic knowledge-based economy tions, there are other processes that can customary limits, or novel combinations in the world” by 2010. To achieve this lead to Technology Transfer and ones of technologies that have been devel- very challenging goal, a number of meas- in which scientific research organisations oped by ESO and made available for ures were planned, including revision of like ESO make significant contributions. industrial exploitation. the framework for state aid for R&D, stim- Many European organisations, including 2. Technologies that have been devel- ulating mobility of researchers between ESA, EMBL, CERN, ESRF as well as oped or extended in collaboration with academia and industry, encouraging Pub- national organisations such as the Max- industry through ESO development lic-Private Partnerships (PPPs), support Planck-Gesellschaft have adopted Tech- contracts. for R&D innovations with Small and Medi- nology Transfer as a core activity, and 3. Technologies that have been devel- um-sized Enterprises (SMEs) as well proactively search for market applications oped or extended by industry through as optimising the mechanisms for Tech- for their technological developments. In the execution of an ESO procurement nology Transfer within Europe. some cases this even extends to promot- contract. ing start-up companies through venture 4. ESO developments that have been Technology Transfer is also being actively capital funds. used for other similar projects else- promoted by the European Competitive- where. ness Council that comprises ministers of 5. ESO patents. research, education and industry or econ- Why is Technology Transfer important omy, as an essential element of improving for ESO? European competitiveness. Examples of Technology Transfer at ESO More than ever before, the governments Although Europe has traditionally been of ESO’s Member States are looking not The following paragraphs give a few rather good at technological innovation, it only at the scientific return but also at the examples of such technologies to illus- has often lagged behind its main indus- industrial return they get from their con- trate the processes just described. trial competitors in exploiting innovations tributions to ESO and the indirect benefits commercially. There are many reasons to their economies and to society as a for this, but one important aspect is the whole. In these days of strained national relatively large contribution made to the budgets, the pursuit of scientific knowl- 1 EIROforum is a collaboration between seven Euro- overall economy in Europe by SMEs. edge alone is not always sufficient to justi- pean intergovernmental scientific research organisations that are responsible for infrastructures and Even before the recent enlargement of the fy the investment into ever more ambitious laboratories (CERN, EFDA, EMBL, ESA, ESO, ESRF European Union, 65 % of the EU GDP and expensive projects. and ILL).

52 The Messenger 121 – September 2005

Figure 1: Diagram showing the principle of Active Figure 2: Example of a Volume Phase Holographic Optics. The Wavefront Sensor detects telescope aber- Grating sandwiched between two prisms to allow rations and misalignments and corrects the shape linear transmission. of the main mirror and position of the secondary mirror to provide real-time correction. In-house developed technologies

Active Optics

The ESO New Technology Telescope (NTT) was the first optical telescope with actively controlled optics. The main driv- er behind this development was to break the classical cost-diameter law for large telescopes but, even at first light, the NTT demonstrated image quality almost never seen previously on ground-based telescopes. Since the NTT, essentially all large optical telescopes worldwide use active optical control. at the time required a complex mecha- A crucial step towards realising a practi- nical system to ensure that the tension in cal active optics telescope was the devel- the tape was always constant and uni- opment of the so-called Shack-Hartmann form. ESO placed a development contract wavefront sensor at ESO. It combines a with Heidenhain to produce an internally compact optical device following an idea mounted tape encoder and provided them originally proposed by Roland Shack at The light passing through a VPHG, in- with a full-sized bearing for tests. The re- the University of Arizona in 1970 with CCD stead of being diffracted by a surface results of this development were so conclu- detectors that started to be used for as- lief pattern as in a classical diffraction sive – in terms of both improved accu- tronomy in the early 1980’s. This device grating, undergoes Bragg refraction as it racy and simplified mechanics – that this allows the optical alignment and shape of passes through a thin transparent layer subsequently became the standard way the main optics of the telescope to be in which the refractive index is modulated. of mounting high-precision strip encoders. measured and corrected in real-time. A This provides a very high optical efficiency key component of the wavefront sen- together with low sensitivity to polarisation sor is the lenslet array which contains and reduced scattering. Technology developed through 400 lenslets, each 0.5 or 1.0 mm across procurement contracts depending on the application. ESO The original VPHGs were produced for worked together with the Paul-Scherrer- Raman Spectroscopy and these were 8-m mirrors – blanks and polishing Institut in Switzerland to develop the small and not ideally suited for astronomy. master and Jobin-Yvon France to manu- A facility to manufacture large Volume One of the main technological hurdles to facture the final copies of these arrays. Phase Holographic Gratings was set up at be overcome for the VLT project was the Centre Spatial de Liège. ESO led a the manufacture of the 8-m blanks for the A number of commercial products based consortium of 5 astronomical institutions primary mirrors. Mirrors of this size had on Shack-Hartmann wavefront sensors that allowed 10 prototype gratings to be never been manufactured before and sev- have since been commercialised, for ex- manufactured up to 30 cm in size. The eral approaches were investigated by ample devices for optical testing by Im- Centre Spatial de Liège has since created ESO. A contract was eventually placed agine Optic in France, for eye surgery by a spin-off company that is the leading with Schott in Germany for the supply Zeiss in Germany and for optical align- European supplier of VPH gratings of the blanks. This necessitated the cre- ment and testing by Spot Optics in Italy. and currently the world’s largest facility for ation of new manufacturing facilities and Shack-Hartmann wavefront sensors are the manufacture of these products. the development of the production pro- widely used in adaptive optics systems cesses for glass-ceramics to completely which correct aberrations caused by new dimensions. The successful com- atmospheric turbulence – a technology Strip tape encoders pletion of the VLT contract put Schott in a that was also pioneered by ESO. leading position to bid for future projects Important components of any large tele- requiring large optics. scope are the high accuracy angular ESO technology development contracts position encoders needed for axis control. The size of the VLT primary mirrors also When ESO originally approached the required a major jump in the state of the Volume Phase Holographic Gratings world’s leading manufacturer of high-pre- art in optical polishing. Indeed, the French cision strip tape encoders, Heidenhain firm REOSC (now part of the SAGEM Since Volume Phase Holographic Grat- in Germany, they could not guarantee that group), who received the ESO contract to ings (VPHGs) were first proposed for the stringent technical requirements polish the four 8-m mirrors, had to build astronomy in 1998, they have had major for the VLT encoders could be met. More- a completely new factory outside Paris for impact on astronomical spectroscopy. over, the tape mounting technique used their manufacture.

The Messenger 121 – September 2005 53 Telescopes and Instrumentation Cullum M., Technology Transfer at ESO

Figure 2: Section through a photonic crystal optical fibre showing the hexagonal pattern of holes that run axially through the fibre. Not only was the size of these mirrors un- eter azimuth drives. Since the VLT, both precedented, but also the required image these firms have expanded into this mar- quality set new benchmarks. Indeed, ket and are now among the world market testing the mirrors proved almost as chal- leaders in this field. PHASE, for example, lenging as polishing them. ESO engineers has recently manufactured the drives worked closely with the manufacturer for the 10-m Gran Telescopio Canarias on to produce a method of specification that La Palma. not only fulfilled the high technical demands of the VLT project and could be verified at the factory, but also made opti- ESO technologies used in other projects mum use of the VLT’s Active Optics system for correcting large spatial frequency Optical design errors. ESO has a unique experience in the field The manufacturing and testing facilities of optical design, covering the wavelength developed by REOSC for the VLT were range from UV to far infrared. Although subsequently used to polish the two to demonstrate the feasibility of this tech- an optical design made for one instrument 8-m mirrors for the US/UK Gemini tele- nology with high laser powers. Since is not readily useable for another, some scope, as well as for smaller optics then, production fibres have been manu- ESO designs have been copied manyfold for other advanced projects. factured by Crystal Fibres and also Mit- for use at other observatories. subishi which meet ESO’s requirements. The ESO Faint Object Spectrograph and Photonic crystal fibres ESO’s developments have been followed Camera – EFOSC – was originally de- with great interest by other laser guide veloped at ESO for the 3.6-m telescope Another technology promoted by ESO is star projects as well as industry because on La Silla. It pioneered the use of new the use of mono-mode optical fibres of the wider commercial implications, for optical glasses for astronomical in- to transmit high power (≈ 10 Watt) visible example in the telecommunications indus- strumentation to produce a very efficient laser beams. These are a key element try and the medical field. As a next step, transmissive optical train. Since that time, of ESO’s Laser Guide Star Facility and are ESO is currently working on the applica- some 15 copies of this design have used to transmit the light from the laser tion of hollow-core photonic crystal fibres been manufactured and put into service laboratory to the launch telescope located to the LGSF, which are now becoming at other observatories around the world. at the very top of the VLT. Compared available. Similarly, the design of UVES – the UV to previous mirror transmission systems, and Visual Echelle Spectrograph devel- fibre-optic transmission allows a signifi- oped by ESO for the VLT has been re- cant reduction in the cost, complexity and Direct drive systems for telescopes produced at least 10 times for application maintenance. elsewhere. Brushless torque motors offer a number However, a fundamental limitation in us- of advantages over conventional tele- Apart from these specific examples, ESO ing classical mono-mode fibres is due scope drive systems, including the elimi- has had a significant impact, through to Stimulated Brillouin Scattering (SBS), a nation of the classical gear train (and optical design proposals and design non-linearity which severely limits the laser hence mechanical simplicity) together with reviews, on the optical design of a very power that can be transmitted through exceptionally good performance. Never- large number of instrumental develop- the fibre. Photonic Crystal fibres – “holey theless, they had never before been used ments in the ESO Member States and fibres” – were first demonstrated in the in large telescopes and nothing of the beyond over the last 25 years. laboratory by researchers at Bath Univer- sizes required for the VLT existed in stan- sity in 1996. These offer an ingenious dard catalogues. way of overcoming the problem of SBS Computer systems and software by allowing an increase in the effective ESO commissioned a study to be carried core diameter of the fibre but without los- out by the Swiss firm ETEL, and the re- Ever since the first “mini-computers” were ing the single mode transmission charac- sults of this confirmed the suitability of introduced at La Silla in the early 1970’s, teristics. This significantly reduces the the concept. In the VLT, direct drives from ESO has been pioneering the use of com- power density inside the fibre and hence ETEL were used in the twelve Adapt- puters for real-time control of telescopes the effects of SBS. er/Rotators, and another specialist firm, and interactive data-reduction methods. PHASE in Italy, was contracted to design This led initially to the development of the Working initially with Crystal Fibre A/S in and manufacture the drives for the four IHAP data-reduction package for spec- Denmark, ESO promoted the develop- Unit Telescopes, including the 10-m-diam- troscopic observations and, in the 1980’s, ment of fibres with characteristics suitable the more versatile MIDAS system which for the LGSF wavelength of 598 nm has been used by several hundred institu- and with good optical transmission tions worldwide.

54 The Messenger 121 – September 2005 More recently, ESO has developed a soft- Knock-on benefits due to ESO’s industrial number of young scientists and engineers ware bundle known as SCISOFT which is procurements over the years. After spending some time a unified collection of the major software at ESO engaged in forefront research or packages for astronomical data analysis There are also secondary industrial ben- developing highly advanced astronomical currently in use today (including IRAF/ efits to firms that receive ESO procure- facilities, these people leave the Organisa- STSDAS, MIDAS and IDL) as well as many ment contracts. A study carried out tion, taking with them their accumulated other utilities. The SCISOFT CD-ROM is by CERN in 20032 amongst firms receiv- professional experience. This benefits not distributed to over 400 institutions world- ing CERN contracts for technology inten- only their future careers, but also stimu- wide per year. sive projects (accounting for about half lates the research in their home institutions of all CERN procurement contracts) con- and helps to improve the competitiveness A fundamental part of the VLT concept cluded that: 38 % of all respondents of Europe’s industries. In 2004, for exam- are the Telescope Control Software developed new products as a direct result ple, ESO employed over 100 Students, and Data Flow Systems that allowed, for of the original contract; 13 % started new Fellows and Associates under these pro- the first time in a ground-based obser- R&D teams; 14 % started a new business grammes. vatory, the complete end-to-end observ- unit; 17 % opened a new market; 42 % ing cycle to be condensed into a single increased their international exposure; Similarly, many ESO engineering staff homogeneous automated process. This 44 % indicated technological learning; and members eventually leave the Organisa- process starts with the preparation of 36 % indicated market learning. tion to return to industry to work on other the observing programme, and continues high-tech projects, taking with them through programme selection, observa- Without the CERN contract, 52 % of all their professional expertise acquired in the tion simulation, automatic or semi-auto- respondents would have had poorer course of their work at ESO. matic execution of the observations at the sales; 21% would have had lower telescope (with or without the presence employment growth; 41% would have Additionally, ESO has organised, either a- of the astronomer at the telescope), quali- had poorer technological performance; lone or with other institutions, many sem- ty control, data archiving and finally and 26 % would have had poorer per- inars, workshops and summer schools on the return of the calibrated data to the ob- formance in valuation growth. diverse scientific topics as well as on server. Although at the outset it was technical aspects such as adaptive optics not easy for many traditional astronomers These data collected by CERN are im- and optics. These events also help to to accept this revolutionary concept, pressive and present additional argu- develop the scientific and technical com- it has become a standard that has since ments for maintaining government sup- petencies within industry and scien- been emulated by most of the world’s port for the Organisation. Although no tific institutions in the Member States. major observatories. In recognition of this similar study has been carried out at ESO, work, ESO was recently presented with the similarities between the two Organisa- Less easy to quantify but also valuable the prestigious 21st Century Achievement tions would lead one to expect that are the personal links established during Award from the Computerworld Honours comparable benefits would also accrue to a period of employment at ESO. Even Program for the Data Flow System as re- ESO suppliers as well. many years later, these personal links can ported in the June 2005 issue of the ESO provide a useful channel for information Messenger. on ESO technologies and programmes Socio-economic benefits of and professional advice. The European ESO Technology Programmes Commission has long since recognised ESO patents the importance of mobility amongst young The fact that ESO actively pursues proj- researchers and engineers for enhanc- In the past ESO has generally preferred ects at the cutting edge of technology ing European competitiveness, and has to openly publish ideas rather than to and maintains a pool of engineering ex- established several programmes to facili- seek patent protection, but in areas where pertise that is probably unique in the tate this. there could exist worldwide commercial world in the field of ground-based astron- application, for example in the commu- omy, also brings socio-economic benefits As can be appreciated from this article, nications industry, patent protection has to the ESO Member States which can the process of Technology Transfer been obtained to allow better regula- also help enhance the economic competi- is many-faceted. It is a process in which, tion of eventual usage through licensing tiveness of European industry as a whole. over the years, ESO has made significant and partnership agreements with indus- contributions, both in encouraging in- try or other institutes. For example, an Through its Student, Fellowship and As- novation in industries within the Member ESO patent has been granted for devel- sociate Programmes, ESO has contrib- States as well as improving commercial opments related to narrow-band high- uted to the training of a considerable competitiveness. power fibre lasers, and a second patent has recently been filed for a high-power 2 fibre laser and amplifier. “Technology Transfer and Technological Learning through CERN’s procurement activity”, CERN2003-005, 11 Sept 2003, Education and Tech- nology Transfer Division

The Messenger 121 – September 2005 55 Other Astronomical News

The ESA-ESO Topical Science Working Groups

Robert A. E. Fosbury (ST-ECF) At the first meeting, it was decided to set During the second meeting in February up a small number of working groups 2005, a new working group was pro- that would examine scientific topics or posed with the intention of reviewing cos- Starting in September 2003, ESO and specific instrumental synergies that would mology with particular emphasis on the ESA have now held two science planning be important over the next decade or investigations of the nature of dark energy coordination meetings in order to en- so. The first of these was on the topic of and dark matter from an astrophysical sure that there remains a joint awareness the search for and the subsequent char- perspective. This new working group on of potential future synergies or missed op- acterisation of extra-solar planets – Fundamental Cosmology was established portunities on the ground or in space. the report of this group, chaired by in June 2005, with John Peacock (Edin- The meetings were attended by the chairs Michael Perryman (ESA/ESTEC) and co- burgh) as Chairman and Peter Schneider (or representatives) of the scientific advi- chaired by Olivier Hainaut (ESO, Chile) (Bonn) as Co-Chairman. It will consider sory committees and by the executives is summarised in the accompanying arti- projects in the areas of dark matter, dark of both organisations. The initiative was cle by Kerber and Hainaut. The second energy, and other aspects of the early taken with the realisation that the two or- was to look at the joint opportunities universe, with the aim of reporting in Feb- ganisations are serving essentially the offered by Herschel and ALMA in the ruary 2006. same scientific communities and share infrared and sub-mm wavebands. Chaired common scientific goals. by Tom Wilson (ESO Garching) and co- The full membership of these groups and chaired by David Elbaz (CEA/Saclay), it is access to their reports as they be- nearing completion and will become avail- come available can be obtained from: able towards the end of 2005. http://stecf.org/eso-esa/

ESA-ESO Working Group on Extra-Solar Planets

Florian Kerber (ST-ECF), the support scientists. A group of ex- The terms of reference provided by ESA Olivier Hainaut (ESO) perts contributed on specific subjects1: and ESO called on the working group to François Bouchy (COROT), Fabio Favata the following: (Eddington), Malcom Fridlund (Darwin), 1. Survey of the Field: this will comprise: The ESA-ESO working group on extra- Anne-Marie Lagrange (Planetfinder), (a) review of the methods used or solar planets was the first of a number of Tsevi Mazeh (Transits), Daniel Rouan envisaged for extra-solar planet detec- such groups to make a careful analysis of (Genie), Stéphane Udry (Radial velocity), tion and study; (b) survey of the asso- scientific fields that are of interest to both and Joachim Wambsganss (Microlensing). ciated instrumentation worldwide ESA and ESO. The groups also make The group operated between June and (operational, planned, or proposed, on recommendations for the development of December 2004 and documented their ground and in space); (c) for each, a the fields facilitating coordinated plan- findings and recommendations to both summary of the potential targets, accu- ning between the two leading European agencies in a report which is available racy and sensitivity limits, and scientific organisations advancing astronomy from in printed form from the ST-ECF and on capabilities and limitations. the ground and from space. both ESO and ESA websites (http:// 2. Role of ESO and ESA Facilities: this www.eso.org/gen-fac/pubs/esaesowg/ will: (a) identify areas in which current The extra-solar planet working group, and http://sci.esa.int/science-e/www/ and planned ESA and ESO facilities will chaired by Michael Perryman (ESA), object/index.cfm?fobjectid=36935). This contribute; (b) analyse the expected consisted of: Olivier Hainaut (Co-chair article gives a very brief summary of the scientific returns and risks of each; (c) ESO), Dainis Dravins (Lund), Alain Léger report and encourages feedback from the identify areas of potential scientific (IAS), Andreas Quirrenbach (Leiden) community. overlap, and thus assess the extent to and Heike Rauer (DLR). Florian Kerber which the facilities complement or and Robert Fosbury from the ECF were 1 The working group membership was established compete; (d) identify open areas which by the chair and co-chair: the report is not a result of merit attention by one or both orga- consultation with the community as a whole. The nisations (for example, follow-up obser- experts contributed considerable information to the report, but the conclusions and recommendations vations by ESO to maximise the return are the responsibility of the members. from other major facilities); (e) con-

56 The Messenger 121 – September 2005 clude on the scientific case for the very 1000 Figure 1: Detection domains for meth- 1 m 0.2 yr 12 yr ods exploiting planet orbital motion, as large facilities planned or proposed. as (1 a function of planet mass and orbital 00 1 p m c) radius, assuming M = M . Lines from 100 as ખ ी As a final step the members of the work- (10 top left to bottom right show the locus p 1 c) ing group came up with a number of 0 µ of astrometric signatures of 1 milli-arc- as (1 sec and 10 micro-arcsec at distances recommendations that will help the further 00 p 10 c) of 10 and 100 pc; Vertical lines show ) development of the field. These are di- J 10 limits corresponding to orbital periods M µ / a rected at both agencies separately but a P s of 0.2 and 12 years. Lines from top M (1 ( 0 p subset specifically calls for joint or coor- s c right to bottom left show radial veloci-

s )

a 1 ties corresponding to K = 10 and

M 1% dinated efforts of the two agencies. Note –1 t K = 1 m s . Horizontal lines indicate e that the recommendations of a similar n S

a photometric detection thresholds for l ESO working group in 1997 (appendix C P 0.1 planetary transits, of 1% and 0.01%, /s U in the present report) directly led to the 10 m corresponding roughly to Jupiter and development of HARPS, the leading spec- Earth radius planets respectively (ne- glecting the effects of orbital inclina- trograph for radial-velocity work today. 0.01 /s 3 tion). The positions of Earth (E), Jupiter 1 m 0 n as (1 (J), Saturn (S) and Uranus (U) are 00 0.01% E p shown, as are the lower limits on the c) masses of known planetary systems Survey of the field 0.001 0.01 0.1 1 10 100 as of December 2004 (triangles). Orbital radius, a (AU) A mere 10 years after the first detection of exoplanets around normal stars, this field has become one of the most active ther, seemingly reliable, planet candidate senger 120, 2005, page 25). HARPS and exciting branches of astrophysics. has been detected through its micro- has demonstrated its capability to explore Detection methods for extra-solar planets lensing signature. A much more detailed the very-low mass end of the exoplanet can be broadly classified into those bas- assessment of the current status, which mass distribution (Pepe et al. 2005, The ed on: is illustrated in Figure 1, can be found in Messenger 120, 22). The VLT Planet Find- (i) dynamical effects (radial velocity, as- the working group’s report. er is expected to make an important con- trometry, or timing in the case of the tribution to the study of bright, well sepa- pulsar planets); The working group surveyed the experi- rated planets for which it is built (there- (ii) microlensing (astrometric or photo- ments that are planned or in prospect, fore belonging to the “population study” metric); and estimated their output qualitatively projects), but its new capabilities will also (iii) photometric signals (transits and re- and quantitatively. Table 1 (see next page), put it in the pathfinder category, and flected light); expanded from a similar table in the one can expect new discoveries in regions (iv) direct imaging from ground or space in report, summarises the situation for the that cannot be explored today. the optical or infrared; and next 15 years. (v) miscellaneous effects (such as magnet- Large, dedicated projects or missions ic superflares, or radio emission). The projects can roughly be classified in are ideal to characterise a whole popula- “pathfinders”, which find new populations, tion: for instance, Kepler is expected Each method has its strengths, and ad- projects characterising populations as to find tens of thousands of planets of a vances in each field will bring specific a whole, and finally projects aiming at de- given type (transiting giants), therefore and often complementary discovery and tailed physical studies. It is crucial to have permitting a detailed study of the global diagnostic capabilities. Detections are a good balance between these three properties of this population. A major a prerequisite for the subsequent steps categories of projects in order to ensure programme using FLAMES for follow-up of detailed physical-chemical charac- at the same time a consolidation of the studies of transit candidates from OGLE terisation demanded by the emerging dis- current knowledge and a long-term devel- has provided physical properties for seven cipline of exoplanetology. opment of the field. planets and has demonstrated that small stellar companions are about as frequent As of December 2004, 135 extra-solar The pathfinders typically expand the ex- as hot Jupiters, emphasising the need planets had been discovered from plored region of parameter space, and will for spectroscopic confirmation and study their radial velocity signature, comprising lead to the discovery of a small number of candidates (Pont et al. 2005, The Mes- 119 systems of which 12 are double of objects, but these define new classes senger 120, 19). and 2 are triple. One of these planets has of planets. NACO on the VLT is a typical also been observed to transit the par- example: the instrument was originally Finally, some experiments are best at per- ent star. Four additional confirmed planets not designed for planet search, but by forming detailed analysis of specific have been discovered through transit de- opening a new window to high-resolution objects. For instance, while the number of tections using data from OGLE (and con- and high-contrast imaging, it led to the planets that it will be able to reach is firmed through radial-velocity measure- discovery of 2M1207b, the first planet de- modest, the VLTI is expected to produce ments), and one, TrES-1, using a small tected by direct imaging, and the first spectra of planets, which will be of 10-cm ground-based telescope. One fur- planet around a brown dwarf. (The Mes- extraordinary value for exoplanetology.

The Messenger 121 – September 2005 57 Other Astronomical News Kerber F. and Hainaut O., ESA-ESO Working Group on Extra-Solar Planets

Method Ground/Space Time Project Pathfinder Population Spectroscopic

> 0.1 MJup / < 0.1 MJup studies Radial Velocity Ground < 2004 First detection Radial Velocity Ground 2004 Harps and others 120/0 Adaptive Optics Ground 2005 NACO First direct detection Few Few Interferometry Ground 2005 VLTI AlI nearby stars Few Some Adaptive Optics Ground 2010 VLT Planet finder New parameter space 20/0 Some Radial Velocity Ground 2010 many 450/20 Transit Space 2008 COROT 200/50 Transit Ground 2010 many 1000/0 Transit Space 2010 Kepler 30 000/1500 Astrometry Space 2015 SIM 250/25 Astrometry Space 2016 GAIA 20 000/0 Transit Space 2016 GAIA 4 000/0 Photometry Space 2016 GAIA Protoplanetary collisions 3 000/0 Interferometry Ground 2015 OWL partially filled 125 000/60 Photo-/Spectrometry Ground 2018 OWL complete 60 “Jupiter” 5 “Earths”

Table 1: Prospects for the coming years. The first col- ESA-ESO facilities establish an offensive policy to optimise umn lists the method used, the second identifies the scientific return of instruments already whether it is a ground-based or space-borne method. The third column gives an approximate time scale. The working group then carefully analysed built or foreseen in the near future. The Project identifies the name or class of the project. The the future needs of research and what second goal is to prepare new initiatives. next three columns summarise the main emphasis role current and planned facilities of ESA Suggested directions are detailed in the of the project, either as pathfinder (few, but significant and ESO can be expected to play. Spe- report. discoveries), or in terms of the number of planets discovered for the projects aiming at defining the popula- cifically they tried to give some answers to tions (detailed for planets more massive and less the following questions: What follow-up massive than 0.1 MJupiter), or finally in terms of detailed observations and facilities are required to First steps towards implementation physical studies of the objects. This table is an ex- characterise these systems more com- panded version of Table 5 in the report. pletely? What does the resulting (statisti- ESO has established a high-level working cal) knowledge of exoplanet distribu- group supervising the implementation Beyond 2015 the current plans call for a tions imply for the targeted observations of the report’s recommendations. A num- detailed characterisation of individual of Darwin and OWL? What information ber of steps have already been initiated. planets and systems. In that framework, will be available, or should be anticipated, For example ESO will study the feasibility OWL could play an important role by for a deeper astrophysical characteri- of a high-resolution spectrograph on searching for targets during its assembly sation of the host stars of planetary sys- the VLT for radial-velocity work and for phase (while the mirror is still partially tems? The working group also looked high-cadence transit spectroscopy. Coor- filled), and then studying them in detail into the potential overlap amongst the dinators have been appointed by both once the mirror is completed. Other major facilities currently planned or stud- ESA and ESO to develop a plan for sup- projects, possibly by interferometry from ied by ESO and ESA. They tried to iden- porting observations from the ground Antarctica and by interferometers and tify specific long-lead time space or for the COROT satellite mission. We are coronographs in space, are also starting ground facilities which should be consid- also carefully looking into the options to be conceived. ered to fill observational gaps anticipated for an amateur involvement in extra-planet over the next 10–20 years? And, finally, research. Finally, ESO is undertaking they looked at other considerations a number of concept studies for OWL in- that ESO/ESA should investigate for strumentation at this point that will also proper interpretation of the data which will address issues related to e.g. the search be generated by these two European for earth-mass planets and the study organisations, or others, and which might of exoplanet atmospheres. ESO and ESA limit the development of the field un- are committed to making sure that less suitably coordinated. From the above the findings and recommendations of the facts and considerations the working ESA-ESO working group are fully appreci- group then came up with recommenda- ated, and are studying how to best imple- tions to the agencies. The first goal is to ment them.

58 The Messenger 121 – September 2005 Other Astronomical News

Report on The ESO-ESA-IAU Conference Communicating Astronomy with the Public 2005 e 1 l Ian Robson b b u

2 H Lars Lindberg Christensen / A S E , n e s l e i

1 N UK Astronomy Technology Centre, UK . H .

2 L

Hubble European Space Agency : o t o

Information Centre, Germany h P

Over one hundred astronomers, public information officers, planetarium specialists and image-processing gurus de- scended on ESO Garching in June for CAP 2005 – Communicating Astronomy with the Public 2005. This was the third international conference addressing astronomy outreach; the previous venues being La Palma and Washington DC. The main aim was to bring together the specialists from the various strands of astronomy undertaking outreach in the broadest sense. The four-day conference was a resounding success, much was The “Credibility discus- achieved and the work of ESO was better sion” at the conference. appreciated (especially from the non- European perspective) through a tour of the facility. Some of the highlights of the high level of both content and presenta- to invitations for information. Web casts local environs were much enjoyed through tional style by all the speakers. The ses- on the other hand promote a somewhat the conference dinner at the Deutsche sions were: 1. Setting the Scene, 2. The less intimate form of talk, as the audience Museum’s aviation museum “Flugwerft TV Broadcast Media, 3. What Makes in principle goes far beyond those in Schleißheim” – (including cockpit tours of a Good News Story?, 4. The Role of the the auditorium. When some of the speak- an F4 Phantom) and a splendid (and well Observatories, 5. Innovations, 6. The Role ers occasionally clearly forgot this, it liquid refreshed) evening at the Augus- of Planetaria, 7. Challenges and New promoted some hasty interjections of the tinerkeller, one of the largest Munich Bier- Ideas, 8. Keeping our Credibility – Release words “Web cast, Web cast” from the gartens. of News, 9. The Education Arena, 10. front row to much amusement from the Astronomical Images – Beauty Is in the audience. The Web casts were also post- The previous meeting in Washington was Eye of the Beholder, 11. Cutting-edge ed online daily during the conference run along a workshop format focussed Audiovisuals, 12. Virtual Repositories and have helped participants afterwards on specific outcomes out of which arose: with the preparation of their proceedings the setting up of a Commission-wide A most successful discussion on credi- papers. Working Group of the IAU; the production bility and the general theme of com- of the Washington Charter (see http:// munication ethics took place in the ses- The “Hands-on” workshop sessions run- www.communicatingastronomy.org/ sion “Keeping our Credibility”, where ning in parallel in the afternoons were washington_charter); and the formulation we were delighted to field a star-studded a huge success and a number were over- of the first principles of an image repo- panel, including the ESO Director General, subscribed. This had been anticipated sitory (in the widest sense). The format of Catherine Cesarsky. in the planning and so the more popular that meeting included breakout session ones were repeated on subsequent days. to debate these issues. CAP 2005 sought Technology and the power of the web The workshops were woven around the to build on these foundations and was much to the fore throughout the con- themes of: image processing; interactions move all issues forward, and as such had ference. The PowerPoint presentations with the media; a communicating toolkit. a number of plenary sessions followed were all posted online on the conference each day by three workshops devoted to website on the same day as the talk Zolt Levay (STScI) and Lars Lindberg four specific topics. took place. Christensen (ESA/Hubble) presented two workshops on basic image process- There were a number of key themes for The live Web casts that were transmitted ing, from image acquisition through the meeting covered in the plenary ses- from the conference were clearly a suc- import with the FITS Liberator to the task sions. Each session was led-off by invit- cess as a number of speakers received of handling multiple layers within Photo- ed speakers and one of the main high- e-mails while at the conference comment- shop. Hubble images were used as lights of the meeting was the extremely ing on aspects of their talk or responding the testbed, so that the participants could

The Messenger 121 – September 2005 59 Other Astronomical News

One of the “Hands-on Workshops” at the conference. experiment and see the changes to the So all those interested in outreach should final image product through different tech- go to the IAU Working Group web-page: niques within Photoshop. http://www.communicatingastronomy.org and enrol on the “Supporters” sign-up Lisa Frattare and Robert Hurt extended sheet so that we can keep you informed this theme with two workshops on more of progress and future events. The pro- advanced image processing ‘tips & tricks’ ceedings of this conference are currently for how to clean and correct the colour being edited and are planned for publica- images as well as make a better com- tion in September. position. Greg Bacon (NASA/STScI) presented a session on how to undertake The organisers wish to acknowledge simple animation studies. Finally in this financial and infrastructure support from theme, Martin Kornmesser and Lars ESO, as well as support from ESA and Lindberg Christensen hosted a session the IAU. devoted to producing your own DVD. Govert Schilling gave two sessions devoted to how to write for the media and

an interactive discussion on the rights and ) 2 ( e l

wrongs of producing a good press re- b b u lease. Terry Mahoney gave an overview of H / A S

the basic contents of a toolkit for astron- E , n e

omers involved in outreach and the do’s ly suggested a possible theme for the s l e i and don’ts of a successful programme. next conference, which will be in 2007. N . H .

There is no doubt that this focused skills- L : s o based workshop-style was extremely The meeting was organised by Ian t o h beneficial and well appreciated by the at- Robson and Lars Lindberg Christensen P tendees. supported by Scientific and Local Organ- ising Committees. The work of the The conference summing-up was under- ‘FITS Liberator’ team was enormous in taken by Professor Paul Murdin (Cam- making the conference both success- Social event: Visit to bridge) who brought together the various ful and right up to the minute in terms of one of Munich’s many themes, tensions and links and additional- technology. Biergartens.

Report on the ESO Workshop on Virtual Observatory Standards and Systems for Data Centres and Large Projects

Paolo Padovani, Markus Dolensky (ESO) tion of common standards between data providers, tool users, and developers. These are being defined using new inter- The Virtual Observatory (VO) is an innova- national standards for data access ger 117, 58) and the logical next step tive, evolving system, which will allow and mining protocols under the auspices from AVO as a deployment of an opera- users to interrogate multiple data centres of the International Virtual Observatory tional VO in Europe (more on EURO-VO in a seamless and transparent way, to Alliance (IVOA: http://ivoa.net), a global in a future issue of The Messenger). best utilise astronomical data. New sci- collaboration of the world’s astronomical ence will be enabled, moving astrono- communities. At the European level, in Data centres lie at the foundation of the my beyond “classical” identification by addition to seven national VO projects, VO, as obviously access to astronomical allowing the characterisation of the prop- the European Community funded collabo- data at all wavelengths is a key require- erties of very faint sources by using all rative EURO-VO is the successor of the ment. The VO cannot (and does not) dic- the available information. The VO requires Astrophysical Virtual Observatory (AVO: tate how a data centre handles its own good communication, that is the adop- e.g., Padovani et al. 2004, The Messen- archive. All that is needed is a VO-layer

60 The Messenger 121 – September 2005 Group photo of the ESO workshop on Virtual Observatory Standards and Systems for Data Centres and Large Projects held from June 27 to July 1 at ESO Headquarters. O to “translate” any locally defined parame- S E , r ter to the standard (i.e., IVOA compliant) e y e H ones. For example, right ascension . H . can be identified in different ways but the H : o t

VO user needs to know which of the o h many parameters accessible through an P archive interface is the right ascension. The longer-term vision of the VO is also to hide away any observatory/telescope/ instrument specific detail and work in astronomical units, for example, “wavelength range” and not grism or filter name. Data providers are then advised to sys- tematically collect metadata (“data about data”) about the curation process, assign unique identifiers, describe the general content (e.g., physical coverage) of a collection, and provide interface and capability parameters of public services. Finally, the VO will work at its best with high-level or “science-ready” data, and data centres should make an effort to provide such data. More specific lectures prepared the par- Finally, the data centre infrastructure tu- To get data providers started in most ticipants for two full days of hands-on tutorial brought all of the above together of the above, the EURO-VO held a work- torials. Several software demonstrations and demonstrated a prototype framework shop at ESO Headquarters in Garching by various VO projects illustrated the cur- supporting the various formats, protocols from June 27 to July 1, 2005. The work- rent capabilities. and concepts. shop was explicitly designed for data centres and large projects to acquire the The seven tutorials took place in parallel Judging from the participants’ feedback, knowledge and experience necessary to sessions and exercises were conduct- which was collected through a question- allow them to become “publishers” in ed on the participant’s own laptops. Up to naire, the workshop was considered “use- the VO. In tutorials and lectures, partici- 100 laptops were on-line through the ful” or “extremely useful” by 95 % of pants were instructed in the use of wireless Local Area Network (LAN), chal- the respondents. The tutorial material (see VO analysis tools, libraries, and the exist- lenging ESO’s excellent internal network below) is a collection of software which, ing web service infrastructure to build VO infrastructure without actually reaching its although still not in a final state, represents compliant services. The workshop was limits. The tutorials dealt with the follow- a unique and up-to-date snapshot of aimed at software engineers and designing topics: Data access layer, that is tools “state-of-the-art” VO technology. ers building archive interfaces, writing and protocols for sharing images and applications accessing remote data, or spectroscopic data; Astronomical Data The workshop agenda and contributions designing archive facilities and data flows Query Language (ADQL)/Skynode, which are available on http://www.euro-vo.org/ for future instruments and missions. is about accessing databases and pub- workshop2005. The tutorial software lishing catalogues; VOTable, the Extensi- was packaged and can also be accessed More than 120 participants, coming from ble Markup Language (XML) VO standard through FTP from the workshop page. 47 different institutions and 16 countries, format for the interchange of data, and It is mostly in Java and works on the most attended the workshop, with representa- the rich variety of tools and libraries to common platforms such as Linux, XP, and tives from 11 out of 15 IVOA members. support it; Metadata, that is how to tag Mac OS. concepts in Astronomy in a machine The workshop started with an overview of readable form using a defined vocabulary the EURO-VO project structure. An intro- called Unified Content Descriptors (UCD); duction on the current status of standard- Grid and web services, namely Informa- isation efforts and international IVOA tion Technology basics and how to set up working groups was then followed by a a service in order to share it on the lo- conceptual approach to the software cal network; Registries, which are places architectures available to publish data to where available resources such as as- the VO. tronomical data collections and software services are described. Participants learned how to set up such a registry as well as how to populate and search it.

The Messenger 121 – September 2005 61 Other Astronomical News

Report on The EPS-ESA-ESO-CERN Conference on Relativity, Matter and Cosmology

Peter Shaver, Bruno Leibundgut, Gravity, including both theory and obser- early universe physics and the achieve- Jochen Liske (ESO) vations, was obviously a major topic at ments of WMAP so far. While he also this conference. As H. Nicolai comment- highlighted the remarkable concordance ed, reconciling general relativity and of present observational results, he went This year the joint ESA-ESO-CERN sym- quantum theory into a consistent and pre- on to emphasise the challenges: “Be- posium was held in conjunction with the dictive theory of quantum gravity is pro- yond Einstein: the physics we don’t know European Physical Society, on the occa- bably the greatest challenge facing theo- and the physics we don’t know how to sion of the Centennial of Einstein’s annus retical physics in the 21st century. He calculate”. He described the potential for mirabilis and the World Year of Physics. described the successes and challenges rapid development in this field, with a It took place on July 11–14 in Bern, where of the two main approaches, superstring whole host of new observational facilities Einstein wrote his famous papers in 1905, theory and canonical quantum gravity. becoming available over the next years. and was part of a wide range of events to C. Everitt described the dedicated space celebrate the centennial. mission Gravity Probe B, designed to ac- Recent breakthroughs in neutrino phys- curately test two aspects of Einstein’s ics, using neutrinos both from the sun and A highlight of these events was the General Relativity: the effect of space cur- the laboratory, were summarised by 13th triennial General Conference of the vature on a free gyroscope and the effect G. Drexlin, including the now conclusive European Physical Society (EPS13), of relativistic frame dragging. It is currently evidence for neutrino oscillations and with the title “Beyond Einstein – Physics collecting data and the first release will be hence for nonzero neutrino masses. He for the 21st Century”. It consisted of in mid-2006. The direct detection of mentioned several open questions, three parallel conferences, one of which gravitational waves has been a dream for and the new round of experiments pro- was the EPS-ESA-ESO-CERN conference decades that may be realised in the near posed to answer them. E. Fiorini sum- on “Relativity, Matter and Cosmology”. future. B. Schutz summarised the physics marised ongoing work on neutrinoless and possible astrophysical and cosmolog- double beta decay, and prospects for the As is usual in these joint conferences, the ical sources of gravitational waves and the detection of weakly interacting massive objective was to provide a broad over- fundamental physics that we may learn particles, a possible candidate for dark view of current and future developments from their detection, and K. Danzmann matter, based on seasonal variations due in the fields of fundamental physics, par- described current and future experiments to the earth’s motion around the sun. ticle physics and cosmology. The fact and their prospects, in particular the J. Bluemer gave a review of the study of that altogether some 600 participants at- planned LISA mission. Pulsars provide cosmic rays since their discovery over tended the three conferences attests to excellent natural astrophysical laborato- 90 years ago, and the current and the interest generated by the wide range ries for tests of General Relativity, and planned experiments to understand the of topics, as well as the wonderful setting D. Lorimer described results over the last astrophysical sources and the extra- in Einstein’s Bern. years and the wonderful prospects with ordinary energies involved. these remarkable systems, like the re- Some 80 talks were given at the confer- cently discovered double pulsar, that are The fundamental problem of the origin of ence on Relativity, Matter and Cosmology, increasingly being found. mass was addressed by G. Ross. He and a substantial number of posters described how explorations of this prob- were presented. In a conference of this Three speakers discussed the current lem have led to extensions of the Stan- size and scope it is difficult to give a state of observational and theoretical cos- dard Model which unify all the fundamen- comprehensive summary, but an idea of mology, and looked to the future chal- tal interactions including gravity; a new the range of the science covered can lenges and horizons. J. Silk discussed the energy frontier may exist which can affect be gleaned from this brief overview based challenges of the cosmic microwave early universe physics and will be probed largely on the invited plenary reviews. background, and stressed the potentially by CERN’s Large Hadron Collider (LHC). great importance of any hints of non- A new state of matter, the Quark-Gluon A stimulating introductory talk entitled gaussianities, unexpected topologies or Plasma, was the subject of J. Stachel’s “100 Years of Relativity” was given by global anisotropies that may be found presentation. She summarised the recent T. Damour. He summarised the remark- (either in the microwave background or experimental support for the existence able success of the theory in a variety of the large-scale distribution of galaxies). of this state, which may have existed in stringent tests, provocatively going on G. Efstathiou gave a talk with the provoc- the early universe until 10 microseconds to ask whether we should now just con- ative title “Is There Cosmological Con- after the Big Bang, and the potential of clude that Einstein was 100 % right and cordance?”. He expressed confidence in the LHC in studying it. F. Iachello gave an stop testing! Of course he then went the concordance of an impressive array overview of symmetries and supersym- on to describe ever more sophisticated of cosmological observations, including metries in nuclei, and placed them in the planned tests, and concluded that new the microwave background, galaxy sur- broader context of complex systems in and exciting frontiers lay before us, veys and supernovae. He made the case general. They, too, will be major targets including the great mysteries of dark mat- for the existence of dark energy, suggest- for the LHC. The huge scientific potential ter and dark energy. ing that it may argue for anthropic rea- of the LHC was described by J. Engelen, sons that we can observe it right now. in particular the possibility of detecting the Finally, D. Spergel gave an overview of Higgs boson; he summarised the status

62 The Messenger 121 – September 2005 of the project, which should become in trying to detect a change in the pro- Finally, J. Liske outlined plans to use OWL, available for experiments in 2007. ton-to-electron mass ratio, also using the VLT’s successor, for the Cosmic W. Gelletley spoke on the broad perspec- VLT data. Dynamics Experiment (CODEX). The aim tives, challenges and opportunities in nu- is to supplement our knowledge of the clear physics, including the upcoming The importance of dark energy to modern universe’s geometry (derived from the new experimental facilities. A different kind physics was emphasised by several microwave background and supernovae) of huge project, the first experimental fu- speakers. Its existence was first estab- with an unprecedented measurement sion reactor (ITER), was described as part lished through observations of distant of its dynamics and hence to provide us of F. Wagner’s comprehensive overview type Ia supernovae and the talks by with a fundamental consistency check of of the current state of plasma physics. R. Pain and J. Sollerman demonstrated General Relativity. that searching for these transient events Possible variations in the fundamental remains a vigorous industry. They out- The sampling above gives some idea of “constants” of physics also generated a lined the two main projects in this field: the wide range of physics and cosmology lot of interest. Recent VLT data have SNLS and ESSENCE. Understanding that was covered at the conference. The contradicted earlier claims of the fine the nature of dark energy was the subject full proceedings of the conference will structure constant having been smaller in of several theoretical talks, involving become available; they will be published the early universe than today. M. Murphy D-branes (P. Gusin), Casimir Energy by the ESA Publications Division as ESA summarised this controversy and de- (R. Garattini), quantum gravity (A. Ernest Special Publication SP-605. scribed ongoing efforts to resolve it. and C. Bryja) and Modified Chaplygin E. Reinhold reported on recent progress Gas (U. Debnath).

ESO Public Activities in July 2005

Prof. Jean Surdej, one of the local organisers, being interviewed by RTL television at the JENAM conference. O

Ed Janssen (ESO) also enjoyed a good media attendance, S E , n

probably also due to the Deep Impact e s s n

Mission. As at previous JENAM meetings, a J . E

The month of July is, in many parts of ESO maintained an information stand : o t o

Europe, considered to be a relatively in the lobby area and participated in the h “quiet time” of the year with many millions press conference. P of people away on summer vacation. Not so for ESO’s Public Affairs Depart- Several ESO staff members gave talks, ment. The month began with a series including the ESO DG, Françoise of press activities around the Deep Impact Delplancke, Henri Boffin, Maximilian Kraus event and included several press con- and Marc Sarazin. Furthermore, a ferences at the ESO Headquarters (mostly Round Table was held to discuss financ- E V I at odd hours!), video press confer- ing, organisation and industrial aspects of J : o t ences with Paranal, La Silla and ESTEC large European astronomical projects. o h in the Netherlands, live TV transmissions It was chaired by Lodewijk Woltjer, former P from ESO Garching as well as from ESO director general. From ESO Roberto Paranal, etc. Gilmozzi participated as a speaker.

In parallel, from July 4–8 the Joint Euro- On July 7, ESO participated in a major pean and National Astronomy Meeting Press Event on the Future of Astronomy (JENAM) took place at the Amphithéâtres Research Infrastructures, organised de l’Europe in Liège, Belgium. The meet- by the European Commission and hosted ing, organised this year by the Astronomy by JIVE, in Dwingeloo, the Netherlands. Department of the Liège University, had The event was attended by EC Research EU Commissioner Dr. Janez Potocnik and Mrs. Maria van der Hoeven, Dutch Minister for Education, Culture the theme “Distant Worlds”. It was attend- Commissioner Janez Potocnik and and Science answer questions from the media repre- ed by over 200 astronomers. The meeting Maria van der Hoeven, Dutch Minister for sentatives at the press meeting in Dwingeloo.

The Messenger 121 – September 2005 63 Other Astronomical News

ESO staff astronomer Thomas Szeifert answers questions at the EPS 13 Open House videoconference at the University of Berne. ) 2 Education, Culture and Science. About A few days later, from July 11–14 ESO ( O S

60 science journalists from across the EU had an exhibition at the University of E , n e attended, together with coordinators Berne, in connection with “EPS 13”. (see s s n a of the various astronomical projects sup- page 60). At the end of the conference, J . E : ported by the EC, including RadioNet, on July 15, an Open Day on Physics and s o t o

OPTICON, EUROPLANET, ILIAS, the ELT Society was co-organised with the Swiss h P Design Study, the SKA Design Study, Academy of Sciences and the Swiss the ALMA Enhancement Programme and Physical Society. In the context of a joint VO-TECH. ESO displayed an informa- EIROforum presentation, ESO partici- tion stand, which was well visited and ap- pated by means of a live video conference preciated by both the participants and the with ESO Paranal, moderated by Barbara media. Vonarburg, well-known Swiss science journalist and Rolf Landua from CERN.

Prof. Jean-Philippe Ansernet, President of the Swiss Physical Society, Prof. Martin Huber, outgoing President of the European Physical Society, Dr. C. Rossel, Conference coordinator, and Dr. Ingrid Kissling-Näf, Director of the Swiss Academy of Sciences at the EPS 13 Conference venue.

Public Information and Education in Chile

Gonzalo Argandoña, Felix Mirabel (ESO) ESO science activities, as described in profundo.cl) was released in advance to Figure 1, which shows the evolution in the emphasise the contribution of the La Silla number of media publications in Chile on Paranal Observatory to the long-term One of the initiatives of ESO in Chile is the recent achievements at ESO. monitoring campaign of Comet 9P/ strengthening of the links with Chilean Tempel 1. This website, that included gen- and Latin American media, to provide the Certainly, the active involvement of the eral information about comets, became information needed to educate the pub- La Silla Paranal Observatory in the global an important reference in the Spanish lan- lic in Latin America on the latest advance- observation campaign of Comet 9P/ guage for the public and journalists who ments in astronomy and astrophysics. Tempel 1 was an excellent opportunity to covered the event. further promote this strategy in a multi- This initiative has produced a consider- approach way. A dedicated website in ESO also joined the Chilean Ministry of able increase in the media coverage of Spanish language (http://www.impacto- Education to organise a national educa-

64 The Messenger 121 – September 2005 tional videoconference (see Figure 2) that ESO Media Coverage in Chile 2004–2005 Figure 1: This graph shows the evolu- linked Paranal with young students in tion of media coverage in Chile of ESO activities, including TV, radio, written No. of Media Publications 18 different cities along the country, from and electronic media, based on inde- Arica (in the Northern extreme of the 250 pendent reports provided by the exter- country) to Punta Arenas (in the Chilean nal company Litoral Press. The peak Patagonia, at the very end of the South 200 on July 2005 is due to the media coverage of ESO observations of Comet American continent). Thanks to this joint 9P/Tempel 1 and Deep Impact. initiative with Chilean authorities, enthusi- 150 astic secondary students could learn about VLT capabilities. 100

In parallel to this educational activity, a 50 series of press events at ESO Vitacura 2004 were offered, with the valuable support of 0 2005 Comet 9P/Tempel 1 observers. The out- March April May June July Month come was a large number of reports and news stories, where observers at Paranal and La Silla played an important role as primary sources of information for editors Figure 2: National videoconference on and journalists. Not all the reports were Comets and Deep Impact, jointly organised by ESO and the Chilean Min- of extreme quality, and precisely one of istry of Education. After a motivating the challenges for the future is to promote introduction given by astronomers lo- in the region best practices in science cated in Santiago and Paranal, stu- journalism and communication of astrono- dents in 18 different Chilean cities had the opportunity to ask their questions my for the general public. about Comets and the Solar System, a few days before impact. A week after the most intensive part of the observing programme of Comet 9P/ Tempel 1 had ended, the main national TV network in the country, in conjunction with ESO, presented a 50-minute documentary. This special chapter showed the excitement behind Comet 9P/Tempel 1 Figure 3: Representing ESO/ALMA, observations, along with some basic prin- Jörg Eschwey, Manager of Site De- velopment at Chajnantor, and Roberto ciples of modern observation of the sky. Tamai, Head of Engineering of the In its first projection by TV, about half a La Silla Paranal Observatory, receive million people watched the documentary the award to the best exhibition during (Source: Time-Ibope). Exponor 2005 (the main industrial convention in Antofagasta, capital of Region II, where Paranal and Chajnan- A complementary approach to this media tor are located). Scale models of the strategy has been the presence of ESO in VLT and ALMA, documentaries in public events and exhibitions, as the Pub- Spanish version and informative panels were part of the ESO-ALMA exhibition. lic Affairs Department of ESO in Garching has done for many years in Europe.

Last June, ESO was present at EXPONOR, the most relevant industrial convention in northern Chile, held every two years (see Figure 3). Based in Antofagasta, it is attended by thousands of visitors, who For the future, more exhibitions in public are the natural neighbours of Paranal and events are expected, most of them in ALMA. collaboration with the Chilean Ministry of Education. In the long run, this will mean an increase on the public awareness of ESO’s commitment with Chile and its people, sharing a cultural identity with the community and contributing to the pro- motion of a science culture and a better understanding of the Universe.

The Messenger 121 – September 2005 65 Other Astronomical News

Universe Awareness for Young Children

George Miley1 verse in later years. Secondly, the educa- introduce the concept of the Sun, the Claus Madsen2 tional disparities between advantaged Solar System, stars and galaxies. Through Cecilia Scorza de Appl 3 and disadvantaged children are smallest excitement, adventure and wonder, for the youngest children. children will be stimulated to appreciate 1 Leiden University the beauty and enormity of the Universe. 2 ESO 3 University of Heidelberg ESO workshop Young disadvantaged children live in diverse environments. For example, the Following the setting up of an ad-hoc educational infrastructure for disadvan- Universe Awareness (UNA) is an inter- UNA steering committee in 2004, a work- taged children in the inner cities of Euro- national programme that will expose shop was held at ESO Headquarters on pean countries is qualitatively different economically-disadvantaged young chil- May 27 and 28, 2005 to discuss the from the situation for disadvantaged children, between ages 4 and 10 years, in feasibility of the Universe Awareness idea. dren in an agricultural African village. developed and developing countries to The 16 participants from 14 countries in UNA will therefore initially develop, imple- the inspirational aspects of modern as- 5 continents included professional astron- ment and evaluate a pilot project in a tronomy. omers, educators, scientific outreach pro- small number of countries representative fessionals and a social anthropologist. of the following three different educational The participants were unanimously enthu- environments: Introduction siastic about Universe Awareness as (i) Environment 1: an idea and about the feasibility of devel- – School starting at age 7–8 or non-exis- From the dawn of history, the beauty of oping it into a useful programme. At tent; the sky and its intimate connection with the workshop two sub-committees were – Television scarce. the development of human civilisation formed to follow up on detailed aspects (ii) Environment 2: have inspired countless generations with of the project. The first is studying educa- – School starting at age 6–7; a sense of wonder. Modern astronomy tional aspects of Universe Awareness, – Sporadic access to Internet; continues to play a unique role in convey- including the content of the programme – Television at home and at school; ing the excitement of science to the and the optimum didactic methods for – Poorly trained teachers. general public. In recent years consider- delivering it. The second sub-committee is (iii) Environment 3: able resources have been devoted to focusing on questions of organisation and – School starting at age 4–5; astronomical outreach in developed coun- funding. – Access to Internet at school and often tries, aided by the spectacular images at home; produced by modern astronomical facili- – Well-trained teachers; ties and the continuing list of major as- The project – UNA accepted as in-school curriculum. tronomical discoveries that have changed our views of the Universe. Universe UNA is intended to be a programme that For each environment a phased, coordi- Awareness is a new programme intended is inspirational and entertaining rather nated modular programme will be pre- to reach a target group that has so far than to impart facts or develop specific pared and training courses will be devel- been neglected by such outreach pro- cognitive skills. The minimum goal will oped, all specifically tailored to fit the grammes, namely children between four be to make young children aware of the culture and language of the target group. and ten years of age. beauty and scale of the Universe. It also carries the implicit message that Nature The programme is motivated by the can be interrogated by rational means. Tools and methods premise that access to simple knowledge The tools and methods of UNA will be about the Universe is a basic birthright developed with the aim of eventually Where very young children do not attend of everybody. The formative ages of four reaching as large a number of children as school (Environment 1), creative appeal- to ten years are crucial in the develop- possible. The development and imple- ing materials will be developed for distri- ment of a human value system. This is mentation of UNA will be driven by the bution by any available delivery method also the age range in which children can needs and wishes of active educators in (e.g. national television or travelling UNA readily appreciate and enjoy the beauty the target countries, combining the in- buses). For Environments 2 and 3, the of astronomical objects and can learn to novative use of professionally developed programme will provide teachers with ma- develop a “feeling” for the vastness of tools, including songs, games, toys and terials that involve children more actively. the Universe. Exposing young children to animation films in a coordinated modular such material is likely to broaden their programme. Several short films will be developed to minds and stimulate their world-view. illustrate the two aspects of Universe The UNA programme will begin with Awareness, beauty and scale and gradu- The programme concentrates on disad- “Earth Awareness”, emphasising that the ally make children aware of the Earth, vantaged young children for two reasons. child is a member of a diverse human the Solar System and the Universe. The Firstly, most other children will be ex- family of children living on a particu- films will be designed to appeal to young posed to some knowledge about the Uni- lar planet. Universe Awareness will then children by entertaining them. They will

66 The Messenger 121 – September 2005 From the UNA workshop at ESO Headquarters.

O Present Organisation of Universe Awareness S E , r e y e H .

H Universe Awareness International .

H Steering Committee : o t o h

P Co-Chairpersons: Mr. Claus Madsen, Head of the Public Affairs Department, ESO, Garching, Germany Prof. George K. Miley, Royal Netherlands Academy Professor, Leiden University, the Netherlands

Dr. Cecilia Scorza de Appl, Landessternwarte Heidelberg, Germany Prof. Alec Boksenberg, Chairman, UK National Commission for UNESCO, Institute of Astronomy, Cambridge, United Kingdom Ms. Alexa Joyce, International Programme Coor- dinator, European Schoolnet, Brussels Belgium

UNA Project Manager Coordinator make use of cartoon characters, anima- example, children would learn from each (from September 15, 2005): Dr. Carolina Ödman, Leiden University, tion and exciting adventure stories. These other that developing countries are often the Netherlands films will be made by experienced makers “richer” in sources of UNA wonderment of children’s entertainment films and than developed ones. For example, skies creative educators, with advice provided in agricultural regions are generally darker Universe Awareness Education Sub-Committee by astronomers. The adventures, featur- and less polluted by light, so that children Chairperson: ing some of the most beautiful images can count much larger numbers of stars. Dr. Cecilia Scorza de Appl, Astronomer/Education- made by modern telescopes, will be set in alist, Landessternwarte Heidelberg, Germany a variety of exotic environments known Special attention will be devoted to opti- Mr. Gonzalo Argandona, Astronomical Outreach, to exist in the Universe. They will attempt mum methods for delivering the pro- ESO, Santiago, Chile to cultivate the sense of imagination that gramme in less developed environments. Ms. Chandra Fernando, Primary School Teacher/ is widespread in young children. Tailoring films to local needs so that they Teacher training, Northeast Montessori Institute, can be transmitted on national or local Baltimore, USA Ms. Birthe Kirknæs, Primary School Headmaster (rtd.), Additional coordinated material tailored television is one option. Another option is Copenhagen,Denmark for each country will be developed with to equip travelling UNA buses with inter- Mr. Jesper Kirknæs, Social Anthropologist, Copen- the aid of talented educators, scientists active games and exciting exhibits. Such hagen, Denmark and artists from these countries. These buses are already frequently used for Dr. Naoufel Ben Maaouia, Educator/Astronomer/Plan- etarium Director, Tunis, Tunisia will include games and songs. They educational purposes in Tunisia, travelling Mr. Bernat Martinez, CEFIRE (In-service Teacher Train- will often focus on the cartoon characters, between widely dispersed villages, stop- ing Centre), Benidorm, Spain feature UNA images and emphasise rele- ping as appropriate. Dr. Premana W. Premadi, Astronomer, Institut vant aspects of Universe Awareness. Teknologi Bandung, Indonesia Dr. Rosa M. Ros, Educator/Teacher training, Technical Where appropriate, involvement of ancient To coordinate the programme and main- University of Catalonia, Barcelona, Spain local cultures with astronomy will be tain links with the schools, teachers, par- Dr. Karl Sarnow, Educator, European Schoolnet, woven into the material. A goal will be to ents and children in the target countries, Brussels, Belgium stimulate active group participation by several Universe Awareness Coordinators Dr. Henri Boffin, Astronomical Outreach, ESO, Garching, Germany the children, where possible, but will also will be trained for each target country. Dr. R. West, Outreach Astronomer (rtd.), ESO, include simple board games that chil- Garching, Germany dren can play on a one-to-one basis. By including a uniform set of characters, Pilot project Universe Awareness Organisation Sub-Committee images and environments over a range of material, the UNA message will be re- We propose to commence Universe Chairperson: inforced. Awareness with a pilot project that will Prof. Alec Boksenberg, Astronomer, Chairman, target a limited number of developing UK National Commission for UNESCO, Institute of Astronomy, Cambridge, United Kingdom Internet will be used to creatively enhance countries and disadvantaged groups in up the programme for disadvantaged to four European countries. There are Ms. Marina Joubert, Scientific Outreach, children in advanced educational environ- two reasons for combining these two tar- South African Agency for Science and Technology ments (Environment 3). Special material get groups. First, the concept of “earth Advancement, Pretoria, South Africa Mr. Claus Madsen, Head of the Public Affairs Depart- will be developed to enable UNA “twin- awareness” provides a good reason for ment, ESO, Garching, Germany ning” activities, for class collaborations linking these two geographically sepa- Prof. George K. Miley, Astronomer, Royal Netherlands between young children in deprived rated target groups. Secondly, a well-de- Academy Professor, Leiden University, the Nether- regions of advanced countries and young fined European involvement in such a lands children in developing countries. For one-world educational programme fits

The Messenger 121 – September 2005 67 Other Astronomical News

well with the aspirations of the European University and the Royal Netherlands Aca- Preliminary Timeline Union and several individual European demy of Arts and Sciences (KNAW). Three stages in the pilot project are envisaged: countries. During the next year we will seek further endorsements. September 2005–December 2006 An “announcement of opportunity” will Preparation be disseminated at the end of 2005, re- The development of the UNA project is – Contacting suitable funding organisations – Refinement of educational goals and needed questing expressions of interest by na- presently being overseen by a 5-member material tional groups that are interested in partici- Universe Awareness International Steering – Preparation of funding proposals pating in UNA. Although the pilot proj- Committee (UNAISC) and two sub-com- ect will concentrate on the selected target mittees devoted to education and organi- 2007–2008 Development countries, UNA material will be made sation/funding respectively. Dr. Carolina – Production of actual animation films, games, toys, available generally. Ödman has been appointed as UNA inter- and internet tools national project manager/coordinator at – Development and organisation of coordinator Leiden from September 15, 2005. training courses Organisations 2009 It is planned to hold a second larger inter- Implementation At present the following organisations disciplinary workshop to discuss pro- – Start of pilot project with evaluation support the Universe Awareness Pro- gress in the project in the late summer of Note that the expected implementation date for the gramme: ESO, the European Schoolnet 2006. All those who are interested in UNA pilot project coincides with the International Year of (ESN), the European Association for and wish to be kept informed of devel- Astronomy planned for 2009. Astronomy Education, (EAAE), the Inter- opments should contact Carolina Ödman national Astronomical Union, Leiden ([email protected]).

Catherine Cesarsky Elected Member of Academies of Sciences y t

On April 20, 2004, the US National Academy of On April 30, 2005, at the Annual Meeting of the e i c o

Sciences selected 72 new members and US National Academy of Sciences, Catherine S l a y

18 foreign associates from 13 countries, includ- Cesarsky, was officially inducted into this highly o R e

ing Dr. Catherine Cesarsky, ESO’s Director prestigious society. h T / s General. This brought the total number of ac- i t a l u

tive members to 1949, including 351 foreign At about the same time, Catherine Cesarsky B . L associates. became a Foreign Member of the Royal : o t o

Swedish Academy of Sciences. Founded in h P Among its distinguished members, the National 1739, this Academy was modelled on the Academy includes 83 astronomers. Catherine pattern of the Royal Society of London and of Cesarsky was elected in recognition of her role l’Académie Royale des Sciences in Paris. It as a pioneer of space infrared astronomy and is an independent organisation whose overall a leader of European physics and astronomy, objective is to foster the sciences, particularly and more particularly, for her seminal contribu- mathematics and the natural sciences. And, tions to the study of star formation in near of course, every year the Academy awards the and distant galaxies, the cosmic infrared back- Nobel Prizes in Physics and Chemistry, the ground, and the confinement and acceleration Bank of Sweden Prize in Economic Sciences in of cosmic rays. Memory of Alfred Nobel, the Crafoord Prize and a number of other large prizes. It might be Catherine Cesarsky is The US National Academy of Sciences is a pri- worth mentioning that this year’s laureates inducted into the vate, non-profit, self-perpetuating society of the Crafoord Prize are three astronomers: British Royal Society. of distinguished scholars engaged in scientific James Gunn and James Peebles from and engineering research, dedicated to the Princeton University, USA, and Sir Martin Rees furtherance of science and technology and to from the University of Cambridge, UK. their use for the general welfare. Upon the authority of the charter granted to it by the On May 27, 2005, Dr. Cesarsky was also elect- has, throughout its history, promoted ex- Congress in 1863, the Academy has a mandate ed Foreign Member of the British Royal So- cellence in science through its Fellowship and that requires it to advise the federal govern- ciety, thereby joining the 1292 Fellows and Foreign Membership, which has included ment on scientific and technical matters. 132 Foreign Members of the world’s oldest sci- Newton, Montesquieu, Darwin, Rutherford, entific academy in continuous existence. Einstein, Hodgkin, Crick, Watson and Hawking. The Royal Society was founded in 1660 and

68 The Messenger 121 – September 2005 Fellows at ESO

Research is the other part of the fellow- My astronomy career started at the Uni- ship, and actually the most important for versity of Oslo where I did my master de- me. Greatly enhanced by a unique ex- gree. During this period, I went on fre- perience of the “backstage” of telescope quent observing trips to the 2.5-m Nordic operations, I can conduct my research Optical Telescope on La Palma, and freely at Vitacura. Even in the context hence got observing experience fairly where none of my colleagues is directly early. To pursue my PhD, I moved to the working in my field. Of course, not every- University of Stockholm. My PhD con- body is aware of the great interest centrated on clustering of galaxies around Wolf-Rayet stars might represent ... But I quasars, but I also worked with weak am slowly making more and more people gravitational lensing by clusters of galax- aware of it! And I realise after these years ies. I still find weak gravitational lensing the advantages of being an ESO fellow: in a very fascinating technique to measure Vitacura there are simply all the “instru- the masses of the largest bound struc- ments scientists” of all ESO instruments! tures in the Universe. And the fellowship is three years in Chile. It gives precious time to start serious During my post doc at the Spitzer Science Cédric Foellmi collaborations, and develop a coherent re- Center I started a programme to study the search. Friends, coherence and sense. centres of nearby radio galaxies, in par- After my studies in Geneva and my PhD Isn’t it what we all are looking for? Some ticular to measure their black hole masses. in Montréal, I moved to ESO and La Silla. lucky ones looking at the beautiful south- For this, I used the historic 5-m Hale tele- Like many others, I was fulfilling a dream. ern sky. scope on Mt. Palomar. During my time I was not only visiting La Silla, but actually here at ESO, I have continued this project working in it! Long turnos provide this using both the NTT and the 3.6-m tele- very peculiar feeling of a little community scope. Being interested in what is going of specialised workers whose goal is to on in the centres of galaxies, I am now observe the sky every night. And the peo- using the new mid-infrared VLT instru- ple in La Silla are really great. As much as ment, VISIR, to study gas in the centres the sky. of active galaxies.

I have been right away attached to the Never did I dream that my interest for NTT. These were hard and great times. astronomy as a kid would take me to so I was still finishing my PhD, and having many different places in this world, and duties at the NTT in the “old” control room: would allow me to meet so many interest- cold, very dry, moving all night. Tough. ing people. This is still an adventure for However, I was not only learning how ESO me! operates, but also how to become an efficient observer on large telescopes. “Ef- ficient” here means having a strong vision of the variety of astronomical objects and phenomena, and a detailed knowl- Margrethe Wold edge of instruments and techniques. This proves to be of the greatest importance I arrived at ESO in the winter of 2003. for my research. I had been working as a post doc at the Spitzer Science Center at Caltech in Pasadena, so arriving in cold Garching was quite a dramatic change from warm and sunny California. From early on, I had a deep interest in science, not just astronomy, but several different topics like archaeology, ornithology and particle physics. In the end, I decided to study astronomy, even though I first started an engineering education at a technical university.

The Messenger 121 – September 2005 69 Announcements

International Conference on Relativistic Astrophysics and Cosmology – Einstein’s Legacy

November 7–11, 2005, Munich, Germany

100 years ago Albert Einstein published Scientific themes are: Invited speakers: three seminal papers on the theories of – Gamma-Ray Bursts – the Creation of Roger Blandford, Jürgen Ehlers, special relativity, of the photoelectric effect Black Holes? Neil Gehrels, Reinhard Genzel, Riccardo and of Brownian motion, which made – Neutron Stars, Black Holes, Micro- Giacconi, Piero Madau, Felix Mirabel, the world call the year 1905 the miracu- quasars Lyman Page, Sterl Phinney, Edward L. lous year. Together with Einstein’s theory – The Galactic Centre and Supermassive Wright. of general relativity fundamental building Black Holes in Galaxies blocks were provided for modern astro- – Active Galactic Nuclei, Feeding and Scientific Advisory Committee: physics and cosmology and can thus be Feedback Roger Blandford, Jürgen Ehlers, Reinhard considered as a true legacy to mankind. – Gravitational Wave Astrophysics Genzel, Günther Hasinger (Chair), – Clusters of Galaxies and Large-Scale Bruno Leibundgut, Gernot Neugebauer, The conference “Relativistic Astrophysics Structure Martin Rees, Hans-Walter Rix, Peter and Cosmology – Einstein’s Legacy” will – Dark Matter and Dark Energy – Schneider, Bernard F. Schutz, Rashid A. give an overview on recent progress in Einstein’s greatest triumph? Sunyaev, Joachim Trümper. relativistic astrophysics and cosmology. It will be one of the final highlights of the Further information and registration: “International Year of Physics” and the www.mpe.mpg.de/~e05/ German “Einstein Year”.

Latin American Astronomy Summer School

December 8–10, 2005, Santiago, Chile

ESO – the European Organisation for As- The lecturers are: Local and Scientific Organising tronomical Research in the Southern Malcolm Longair (Cambridge University, Committee members are: Hemisphere – and the Sociedad Chilena UK), Bob Williams (STScI, USA), Gloria Felix Mirabel (ESO – Chair), Monica Rubio de Astronomía (SOCHIAS) are organising Dubner (IAFE/CONICET, Argentina), (Universidad de Chile), Dante Minniti a Latin American Astronomy Summer Pat Osmer (Ohio State University, USA), (Pontificia Universidad Católica, Chile), School. It will take place from December Luis Felipe Rodriguez (UNAM, Mexico), Maria Eugenia Gomez (ESO), and Andrea 8–10, 2005, the week before the Regional Dante Minniti (Pontificia Universidad Lagarini (ContactChile Comunicaciones). Meeting of the International Astronomical Católica, Chile), Felix Mirabel (ESO, Chile). Union to be held on December 12–16, The School e-mail is [email protected]. 2005 in Pucon, Chile (~ 800 km South of The lectures will cover the following Interested participants should fill in the Santiago). themes: preregistration form at the webpage link: – Extrasolar planets www.sc.eso.org/santiago/science/LASS2 The aim of this multi-thematic Latin Amer- – Star Formation and the Interstellar 005/ ican School is to provide students and Medium young researchers exposure to different – Supernovae There is no registration fee, and limited front-line areas of research presented by – Black Holes funds may be available to cover local ex- major players in promoting and/or execut- – Evolution of Galaxies. penses in Santiago. The School an- ing those areas. The lectures will have a – Distant Quasars nouncements will be posted; check for pedagogical character. – The Deep Universe updates at: www.sc.eso.org/santiago/ science/LASS2005/ This School is sponsored by: ESO, SOCHIAS, and the I. Municipalidad de Vitacura.

70 The Messenger 121 – September 2005 Personnel Movements

July 1, 2005–September 30, 2005

Arrivals Departures

Europe Europe

Alves de Oliveira, Catarina (P) Student Blondin, Stephane (F) Student Fedele, Davide (I) Student Credland, John D. (GB) Head of the ALMA Division Feng, Yan (CN) Paid Associate Da Costa, Luiz Alberto (I) Astronomer Hötzl, Stefan (D) Electronics Technician Döllinger, Michaela (D) Student Igl, Georg (D) Quality Engineer Fechner, Matthias (D) Student Kolb, Johann (F) Paid Associate Gerken, Bettina (D) Student Kornmesser, Martin (D) Graphics Designer Guzman, Ronald (BOL) Student Landsmann, Michael (D) Student Hastie, Morag Ann (GB) Student Lapeyre, Pascal (F) Engineering Work Järvinen, Arto (FIN) Student Lopez, Gil Ignacio (E) Accountant Kalaglarsky, Damyan (BG) Student Lyubenova, Mariya (BG) Student Karl, Simon (D) Student Manescau, Hernandez Antonio Ramon (E) Instrumentation Engineer Kniazev, Alexei (RU) Paid Associate Mieske, Steffen (D) Fellow Koenig, Emilie (F) Student Rivas, Rodrigo (RCH) Student Landsmann, Michael (D) Student Rykaczewski, Hans (D) Head of the ALMA Division Renzini, Alvio (I) VLT Programme Scientist Vernet, Elise (F) Paid Associate Rivas, Rodrigo (RCH) Student Wesse, Yves (F) Contract Officer Rolland, Lucie (F) Student Sartoretti, Paola (I) Operations Scientist Valat, Bruno (F) Student Verdoes Kleijn, Gijsbert (NL) Fellow Zhuang, Tao (CN) Student

Chile Chile

Aguilera, Hugo Freddy (RCH) Accounting Officer Aguilar, Raul (RCH) Safety Engineer Amico, Paola (I) Operations Astronomer Baes, Maarten (B) Fellow Badel, Arnaud (F) Student Billeres, Malvina (F) Fellow Dierksmeier, Claus (D) Civil Engineer Couronne, Cristophe (F) Student Groothuis, Charlotte (NL) Opto-Mechanical Engineer de Brito Leal, Luis Filipe (P) Student Guniat, Serge (CH) Mechanical Engineer Ederoclite, Alessandro (I) Student Lassalle, Jacques (F) Safety Engineer Fossati, Luca (I) Student Luhrs, Javier (RCH) Software Engineer Haubois, Xavier (F) Student Mella, Juan Alberto (RCH) Safety Engineer Hurtado, Norma (RCH) Telescope Instruments Operator Schmidtobreick, Linda (D) Operations Astronomer Jaunsen, Andreas (N) Operations Astronomer Leproux, Anais (F) Student Martinez, Mauricio (RCH) Telescope Instruments Operator Roa, Mauricio (RCH) Software Engineer Scatarzi, Alberto (I) Student

ESO – European Organisation for Astronomical Research in the Southern Hemisphere

invites applications for the position of a Qualification and Experience: Advanced university degree in Science, preferably astronomy/astro- European Affairs Officer physics. Knowledge of contemporary science policy isues as well as of the EC Framework Pro- Assignment: The successful candidate will gramme and other European funding schemes is – Identify relevant funding possibilities within the required. Experience in interaction with science EC Framework Programme and other activities, administrators and policy makers at all levels is advise applicants and monitor the progress necessary. Experience in public science communi- of applications and contracts; cation and interest in societal aspects of science – Follow developments in European Science Policy are an advantage. Fluency in English is essential and provide advice to the ESO management; as well as a good knowledge in French. – Assist with ESO’s interaction in the EIROforum partnership; Duty station: Garching near Munich, Germany – Organise policy-related debates and events in Starting date: As soon as possible member states as well as in the institutions Further information under: http://www.eso.org/ of the EU, attracting key decision-makers and gen-fac/adm/pers/vacant/europeanaffairs.html media; – Organise special visits and events for opinion formers and target groups in member states. ESO. Astronomy made in Europe

The Messenger 121 – September 2005 71

ESO is the European Organisation for Contents Astronomical Research in the Southern Hemisphere. Whilst the Headquarters I. Hook et al. – Science with Extremely Large Telescopes 2 (comprising the scientific, technical and administrative centre of the organisa- Reports from Observers tion) are located in Garching near H.-U. Käufl et al. – Deep Impact at ESO Telescopes 11 Munich, Germany, ESO operates three A Triple Asteroid System 17 observational sites in the Chilean Ata- S. Randich et al. – FLAMES Observations of Old Open Clusters 18 cama desert. The Very Large Telescope W. Gieren et al. – Measuring Improved Distances to Nearby Galaxies: (VLT), is located on Paranal, a 2 600 m The Araucaria Project 23 high mountain south of Antofagasta. At C. Péroux et al. – Early Galaxy Evolution: Report on UVES Studies La Silla, 600 km north of Santiago de of a New Class of Quasar Absorbers 29 Chile at 2 400 m altitude, ESO operates A New Einstein Ring 32 several medium-sized optical tele- M. Swinbank et al. – Resolved Spectroscopy of a z = 5 scopes. The third site is the 5 000 m Gravitationally Lensed Galaxy with the VIMOS IFU 33 high Llano de Chajnantor, near San Farthest Known Gamma-Ray Burst 35 Pedro de Atacama. Here a new submil- M. J. Jarvis et al. – Surveying the High-Redshift Universe with the VIMOS IFU 38 limetre telescope (APEX) is in opera- S. Lilly et al. – The zCOSMOS Redshift Survey 42 tion, and a giant array of 12-m submil- Observing with the New High-Speed Camera ULTRACAM on Melipal 46 limetre antennas (ALMA) is under development. Over 1600 proposals are Telescopes and Instrumentation made each year for the use of the ESO T. Wilson – ALMA News 48 telescopes. J. Eschwey – ALMA Site Development 50 M. Cullum – Technology Transfer at ESO 52 The ESO MESSENGER is published four times a year: normally in March, June, Other Astronomical News September and December. ESO also R. A. E. Fosbury – The ESA-ESO Topical Science Working Groups 56 publishes Conference Proceedings and F. Kerber, O. Hainaut – ESA-ESO Working Group on Extra-Solar Planets 56 other material connected to its activities. I. Robson, L. L. Christensen – Report on the ESO-ESA-IAU Conference Press Releases inform the media about Communicating Astronomy with the Public 2005 59 particular events. For further infor- P. Padovani, M. Dolensky – Report on the ESO Workshop on Virtual mation, contact the ESO Public Affairs Observatory Standards and Systems for Data Centres and Large Projects 60 Department at the following address: P. Shaver et al. – Report on the EPS-ESA-ESO-CERN Conference on Relativity, Matter and Cosmology 62 ESO Headquarters E. Janssen – ESO Public Activities in July 2005 63 Karl-Schwarzschild-Straße 2 G. Argandoña, F. Mirabel – Public Information and Education in Chile 64 85748 Garching bei München G. Miley et al. – Universe Awareness for Young Children 66 Germany Catherine Cesarsky Elected Member of Academies of Sciences 68 Phone +49 89 320 06-0 Fellows at ESO – C. Foellmi, M. Wold 69 Fax +49 89 320 23 62 [email protected] Announcements www.eso.org International Conference on Relativistic Astrophysics and Cosmology – Einstein’s Legacy 70 The ESO Messenger: Latin American Astronomy Summer School 70 Editor: Peter Shaver Personnel Movements 71 Technical editor: Jutta Boxheimer Vacancy notice 71 www.eso.org/messenger/

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© ESO 2005 Front Cover Picture: The Radio Galaxy Centaurus A ISSN 0722-6691 This image (NGC 5128) was obtained by João Alves and colleagues using the WFI instrument mounted on the 2.2-m ESO telescope of La Silla. This composite colour image is a combination of five filters (U, B, V, R and Hα). The observations were reduced and combined by Benoît Vandame (ESO).