Astronomical News

Study conclusions tion which exceeds that contained in the role in the decision of employees to use ALMA High Altitude Visitors Information OSH programmes or not. With improved From the perspective of visitors/workers packet and the site safety instruction by attractiveness and marketing of the ma- at high altitude, the results of this study the site safety officer, was sometimes terials/programmes on the one hand, and document fewer problems than ex- mentioned in the questionnaire returns. organisational culture and safety leader- pected. The visitors/workers neither re- This diligence implies that high-altitude ship on the other, we have the necessary ported major psychosomatic complaints safety and health issues are seriously tools to win over everyone to an ap- nor impairment of abilities, work behav- considered also by visitors – an indication propriate preparation for and use of OSH iour or work performance. However, the that most of them were concerned about materials/programmes. data indicated some areas worthy of visiting a high-altitude site and, there- further study that bear potential improve- fore, were interested in getting useful ment for OSH programmes, such as con- background information. References centration/awareness problems, fatigue/ Böcker, M. & Vogt, J. 2007, The Messenger, 127, 64 under-arousal and reduced capacity. Although only a minority of participants Fields, R. D. 2008, Scientific American, Although not statistically significant from did not report about preparations for April/May 2008 the study so far, workers generally re- ascent to high altitude, serious incidents Sakamoto, S., et al. 2003, ALMA Memo, 446 port slightly more problems at high alti- may be more likely to happen to indi- Vogt, J. 2002, in Lehrbuch der Umweltmedizin, ed. Dott, W., et al., (Stuttgart: Wissenschaftliche tude than visitors. However, cultural dif- vidual high-altitude visitors/workers with Verlagsgesellschaft mbH), 479 ferences, for example, optimism of local reduced safety consciousness. Thus, we Vogt, J., et al. 2004, International Journal of Emer- workers versus critical view of visiting sci- need to find out how to convince every- gency Mental Health, 6, 185 entists, probably also play a role. body to adequately prepare for the work Vogt, J., Pennig, S. & Leonhardt, J. 2007, Air Traffic Control Quarterly, 15, 127 at very high altitude. This finding is in line West, J. B. 1997, Aviation Space and Environmental With respect to the preparations for high- with other studies, for example, with Medicine, 68, 162 altitude work and the benefits of OSH air traffic controllers, who in two thirds of West, J. B. 2003, ALMA Memo, 477 programmes, one result of this pilot study cases concerning critical incidents West, J. B. 2004, The Observatory, 124, 1 Wu, T., et al. 2007, High Altitude Medicine & Biology, is that some participants did not report had attended a stress management pro- 8, 88 any preparation in matters of safety for gramme and in one third had not (Vogt their work at high altitude. The remaining et al., 2004; 2007). The latter third dem- visitors and workers, who reported on onstrated a reduced performance for their preparations, mostly used more than a longer period after an incident. The one method. Some visitors have done organisational culture and the safety atti- more than expected. Additional informa- tude of supervisors play an important

Report on the ESO and Radionet Workshop on Gas and Stars in Galaxies – A Multi-Wavelength 3D Perspective held at ESO Garching, Germany, 10–13 June 2008

Matt Lehnert1 An overview of the ESO/Radionet work- near-IR and sub-mm/radio communities Carlos De Breuck 2 shop devoted to 3D optical/near-infra- working on three-dimensional (3D) extra- Harald Kuntschner 2 red and sub-mm/radio observations of galactic data. The meeting was attended Martin Zwaan 2 gas and stars in galaxies is presented. by more than 150 scientists. This article, There will be no published proceedings due to space limitations, provides a, but presentations are available at http:// necessarily biased, overview of the meet- 1 Laboratoire d’Etudes des Galaxies, www.eso.org/sci/meetings/gal3D2008/ ing. We decided not to publish proceed- Etoiles, Physique et Instrumentation program.html. ings, but the presentations are available (GEPI), Observatoire de Paris-Meudon, from the workshop homepage at http:// France www.eso.org/sci/meetings/gal3D2008/ 2 ESO The main aim of this ESO/Radionet work- program.html. The names of speakers rel- shop was to bring together the optical/ evant to a topic are included here so that

52 The Messenger 133 – September 2008 NGC 3607 NGC 3610 NGC 4026

Stellar V Stellar V [OIII] V

NGC 4526 UGC 3960 Numerical Simulation

CO H I

Figure 1. The Atlas3D project (http://www-astro. current studies of neutral hydrogen out to the Atlas3D project with the SAURON physics.ox.ac.uk/atlas3d) includes a multi-wave- cosmological distances and will provide imaging spectrograph (presentation by length coverage of a complete sample of nearby early-type galaxies, including optical IFU, CO and H I information on the cool gas in and around Michele Cappellari, see Figure 1) that data combined with a specific effort on numeri- galaxies. All of these devices and tech- early-type galaxies show a surprising cal simulations. Illustrations of the Atlas3D datasets niques are necessary if we are ever going amount of rotation. This was not apparent are shown, from top left to bottom right: stellar to understand the complex interaction previously because of the narrow range velocity maps of NGC 3607 and NGC 3610; ionised gas velocity map of NGC 4026; CO velocity map between gas and stars in galaxies. of magnitudes and the limited number of of NGC 4526; H I contours of UGC 3960; and a pro- the galaxies in earlier surveys. Less lumi- jected snapshot of a numerical simulation. It was clear from the meeting that we nous, and more numerous early-type gal- are indeed learning a great deal about axies tend to show more rotational sup- further reference to the presentations can the detailed relationships between gas port than their more massive and rarer be made through the web page. phases in galaxies, how star formation cousins. So most early-type galaxies are proceeds, and how the global environ- lenticulars and not ellipticals. These ob- The optical/near-IR community now has ment within galaxies affects these rela- servations can plausibly be explained by access to an increasing number of pow- tionships. Perhaps uniquely emphasised mergers with a range of mass ratios that erful Integral Field Units (IFUs; see pres- at this meeting was the important role are typically 1:2 or 1:3 (Thorsten Naab). entation by Eric Emsellem) and the sec- that instrumentation, especially those But of course, the final result depends on ond-generation VLT instruments, as well that provide three-dimensional (spatial the initial orientations and amplitude of as the proposed E-ELT instruments, will and spectral) information, can play in our the various angular momentum vectors of all have IFU units (Niranjan Thatte). These overall understanding of star formation the progenitors and the orbit (Maxime instruments will thus provide large data and galaxy evolution. Bois). However, there were some puz- cubes sampling the stellar content and zling, and perhaps alarming, comments the warm/hot ionised gas. that these merger models, while perhaps Early- and late-type galaxies explaining the large-scale dynamics, can- Radio and millimetre interferometers have not account for the orbit families within provided 3D information on gas in gal- One of the most fascinating themes of early-type galaxies. Obviously, the exqui- axies for decades (Thijs van der Hulst). the conference was the nature and con- site 3D data that we are able to produce ALMA will – by design – always provide tinuing growth of early type galaxies. The is a real puzzle for modellers (Mathieu high spatial and spectral resolution data paradigm that early-type galaxies always Puech). cubes of the cold gas (Robert Laing), mean pressure-supported systems with allowing the molecular and dust distribu- no recent star formation, and certainly no It also appears that we can watch the tion to be traced in galaxies. Future accreted gas, has been consigned to growth of structure within early-type gal- radio facilities (Philip Diamond) will extend historical novelty. It appears now through axies. By studying the CO and H I emis-

The Messenger 133 – September 2008 53 Astronomical News Lehnert M. et al., Report on the Workshop on Gas and Stars in Galaxies

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Figure 2. Comparison of CO and optical 3D data for Late-type star-forming galaxies in the Active galactic nuclei and black holes NGC 3032. Left: Stellar mean velocity field, overlaid local Universe are also full of surprises. with contours from the integrated/total CO(1–0) map (Young et al., 2008). Right: CO mean velocity field, There are several theories for explaining What is the role of active galactic nuclei overlaid with the optical (roughly V-band) isophotes how star formation is driven on large (AGN) in galaxy formation and evolution? (Emsellem et al., 2004). scales – from gravitational instabilities, to The relationship between the mass of such instabilities aided by magnetic the supermassive black holes and the sion from early-type galaxies, it is possi- fields, to large-scale convergent flows or mass of their surrounding spheroids is ble to observe a relationship between density fluctuations in the gas. Recent one of the most remarkable relationships gas content and the dynamical properties multi-wavelength observations in the opti- in astrophysics and suggests an under- and ages of the stars in their circum- cal, H I and CO of star-forming galaxies lying connection between galaxies and nuclear regions. For example, even though indicate that molecular gas forms with black holes. However, is this relationship this relation can only be measured for fixed efficiency, that giant molecular cloud universal across all spheroid masses? a relatively short time, due to rapid fading, populations are universal, but that the The answer appears to be yes at the low- ~ 20 % of early-type galaxies show evi- formation of molecular clouds clearly mass end of spheroid mass (talks by dence for young stars in their circum- depends on the large-scale environment Roberto Saglia and Davor Krajnovic) but nuclear regions (Martin Bureau) and over- (contribution by Adam Leroy, see Fig- perhaps not at the high-mass end. Where all there appears to be a relationship ure 3). This universality of molecular does this relationship come from? It between young ultraviolet bright discs, clouds was emphasised by comparing could be due to a self-limiting cycle of CO emission, and young stars and star the clouds in our own Milky Way with black hole growth, followed by kinetic formation (see Figure 2). In fact, it ap- those of other galaxies (Alberto Bolatto). energy from the AGN quenching both pears that such star-formation events fol- These data seem to disfavour the primary star formation and further accretion by low the relation between the star-forma- role of magnetic fields in star formation, the black hole. Active galaxies appear tion rate and the gas-surface density but are currently limited by the sensitivity to have a greater incidence of streaming relation – the so-called Schmidt-Kenni- of the tracer CO emission to optical motions in the large-scale gas distribu- cutt relation (Martin Bureau). Even though depth effects. Obviously much more work tions (Gaelle Dumas), which then might such observations are just beginning, needs to be done to constrain star-for- reach the nucleus through torques on it is already clear that early-type galaxies mation theories, which are so critical to the gas (unlikely), but perhaps viscosity is can contain a significant amount of our understanding of galaxies. a more likely mechanism, and finally neutral hydrogen (10–15 % of which have 10 9 –10 solar masses of H I; Raffaella

Morganti) with a hint that perhaps galax- 600 ies with centrally concentrated H I also have younger stars in their nuclei. These observations may also explain the dichot- 700

omy in ‘kinematically decoupled cores’ ) s Figure 3. Major axis / m k ( (KDCs), that is a core which has different 800 position-velocity dia- y t i c

o gram of NGC 3521. kinematics to the surrounding galaxy. l e Large KDCs appear to have formed long V Greyscales are neutral 900 hydrogen 21-cm emis- ago, while smaller KDCs appear to sion from the THINGS have formed rather recently (results by project (Walter et al., 2008). The colours rep- the SAURON team, reported by Martin 1000 Bureau). This difference is likely to be resent HERA CO emis- sion (HERACLES, PI: related to recent gas accretion as seen Adam Leroy). Picture 11h 05m09s 05m50s 06m00s in mm- and cm-wavelength observations. Right Ascension (J2000) credit: Erwin de Blok.

54 The Messenger 133 – September 2008 this may lead to both star formation and accretion onto the black hole (Eva [−154, +154] [−154, −22] [+22, +154] Schinnerer). But what comes first, the supermassive black hole or the galaxy? Dynamical masses derived from CO observations of very high-redshift power- ful AGN (Figure 4) suggest that super- massive black holes become very mas- sive before their galaxies have grown substantially. In fact, instead of being about 0.1% of the total bulge mass, the black hole mass at z ~ 6 it is more like 3 % (Fabian Walter)! When they do get fuelled, the AGN, or at least the radio- loud AGN, can drive vigorous outflows of the type necessary to suppress further 1 kpc 1 kpc star formation and black hole growth (Nicole Nesvadba). But it also appears as if the halos of radio galaxies might have Figure 4. CO velocity field of the z = 4.4 interacting significant amounts of H I, up to 1011–12 galaxy BRI 1335 (Riechers et al., 2008), with the velocity of the gas colour coded. The left panel solar masses, as probed by resonantly shows the whole velocity range (indicated in the scattered Ly-alpha radiation (Joshua top), while in the right panel the contribution of gas Adams). around the systemic velocity of the galaxy is ex- cluded, emphasising the outflows. What processes drive the growth of mass in galaxies? What are the relative roles ies. Tidal dwarfs, formed out of the tidal suggested that these observations are of gas accretion, from the dark matter arms that are generated during the merg- apparently not consistent with a signifi- halo and surroundings, versus merging er process, helping us to understand the cant role of mergers (Kristen Shapiro), but with other galaxies as the driving force for properties of star formation in differing rather with a simple settling of discs over the star-formation history of the Universe? environments, can also provide important many dynamical times (Natascha Förster This debate was joined in the meeting information about the nature of dark-mat- Schreiber, see Figure 5). The star-for- from several different directions. Direct ter halos (Pierre-Alain Duc). Three-dimen- mation rates in high-z galaxies appear to observations of gas accretion in nearby sional observations of high-redshift gal- be consistent with gas accretion from galaxies are scant. The amount of H I axies (z ~ 2) in the rest-frame optical and hier archical merging models, as well as seen in the halos of galaxies is relatively mm, on the other hand, emphasised the the star-formation properties like local insignificant (talks by Filippo Fraternali, role of gas accretion. Some participants discs (talks by Nicolas Bouché, Helmut George Heald and Tobias Westmeier) and its origin is unclear (George Heald). Per- haps these are not the correct type of observations, and this accreting gas is in another phase yet to be probed. The role and nature of mergers in the local Uni- verse is of course not disputed. The most actively star-forming galaxies in the local Universe are gas-rich mergers and pro- vide an important testing ground for our theories of star formation in active en- vironments (presentations by Christine Wilson and Susanne Aalto), even if we do not understand completely how they evolve (John Hibbard). In such environ- ments, with their high optical depths, it is important to probe the gas in a number of molecular species, thus providing information about the physical conditions within the gas (talks by Susanne Aalto and Masatoshi Imanishi). Mergers may Figure 5. H-alpha velocity field of the also play an important role in our under- z = 2.38 galaxy BzK-15504 obtained standing of the environments of galax- with SINONFI+AO (from Genzel et al., 2006).

The Messenger 133 – September 2008 55 Astronomical News Lehnert M. et al., Report on the Workshop on Gas and Stars in Galaxies O S , E r e y e . H . H : H o t o h P

Figure 6. The conference participants group photograph taken just in front of the Max-Planck-Institut für Plasma- physik lecture theatre.

Dannerbauer and Mark Swinbank). How- alisation techniques. Of course, mm- and second-generation VLT instruments) ever, it also appears that there is a great cm-wave astronomers have been using being planned or developed will only add deal of diversity in the observed molecu- 3D visualisation techniques for decades to this happy state of affairs. However, lar properties of high-redshift populations (Thijs van der Hulst) but these are still rel- what was also clear from the discussions (Pierre Cox). atively new for optical and near-infrared during the meeting is that we need to de- astronomy (Giovanni Cresci). Particularly velop our theoretical understanding and Of general concern with high-redshift gal- interesting are the techniques being used modelling techniques to be able to truly axy studies is the low spatial resolution. in medical imaging and diagnosis (de- take advantage of our new observational At z = 2, the scale is about 8 kpc per arc- scribed by Neb Duric). While often in a abilities. While overall the meeting was second; thus with seeing-limited, or even different regime (higher resolution and optimistic about the future of research adaptive-optics, observations the reso- signal-to-noise), medicine is producing into gas and stars in galaxies, it was also lution is no better, and often much worse, a number of powerful techniques to look obvious that we have a lot more to learn! than 1 kpc. Strongly lensed galaxies, for subtle relationships in three-dimen- however, offer the opportunity to obtain sional (and four-dimensional!) data. The physical resolutions of ~ 100 pc and vast explosion in data rates in astronomy References investigate the fine-scale relationships should also not be overlooked. How Emsellem, E., et al. 2004, MNRAS, 352, 721 between the optical emission-line gas are we going to handle this flood of data? Genzel, R., et al. 2006, Nature, 442, 786 and the molecular gas (as exemplified in Visualisation should make more use of Riechers, D., et al. 2008, ApJL, submitted talks by Mark Swinbank and Andrew the computing power of modern Graphi- Walter, F., et al. 2008, ApJ, in press Bunker). As such, this is a powerful tech- cal Processing Units, developed for the Young, L. M., Bureau, M. & Cappellari, M. 2008, ApJ, 676, 317 nique for studying the phenomenology computer game industry (Chris Fluke). Of of distant galaxies, such as their ability to course the raison d’être of the Virtual drive winds, and investigating whether Observatory is to make this vast quantity or not their star formation is similar to of data, with all its complexity, available that in the local Universe. In the mm re- to the community (Igor Chilingarian). gime, ALMA will have a significant impact (talk by Robert Laing), as is already illus- In summary, it was clear from the myriad trated by the new extended baselines of of physical processes, which must be the IRAM Plateau de Bure interferometer understood in order to understand galax- (Pierre Cox). ies and star formation, that we have our work cut out for us. The amount of detail A very important component of this that the current generation of 3D facilities meeting, and one that perhaps makes it is revealing in galaxies is quickly advanc- unique for a meeting of this kind, was the ing our knowledge. The next generation various talks on data reduction and visu- of observing facilities (e.g. ALMA and the

56 The Messenger 133 – September 2008