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Ultraluminous infrared galaxies (ULIRGs) are probably the local analogues of a major mode of galaxy formation in the early universe. Here we give a brief progress report on our ongoing programme to study the nature and evolution of ULIRGs. Our near-IR imaging of a large sample of these highly disturbed merger systems provides a data base of morphological parameters like tidal features or projected separation of the nuclei. Together with ISO Mid-IR spectroscopy these morphological parameters allow us to explore the merger dynamics and evolution of ULIRGs as they may progress from starburst to buried AGN to exposed QSO. We find that the fraction of ULIRGs predominantly powered by AGNs increases with luminosity above ~ 3 x 1012 L ⊙, but that there is no obvious trend for ULIRGs to be more AGN-like with more advanced merger phase.

We describe the design, development, and performance of HAWK-I, the new High-Acuity Wide-field K-band Imager for ESO’s Very Large Telescope, which is equipped with a mosaic of four 2 k × 2 k arrays and operates from 0.9−2.4 μm over 7.5 � × 7.5 � with 0.1 �� pixels. A novel feature is the use of all reflective optics that, together with filters of excellent throughput and detectors of high quantum efficiency, has yielded an extremely high throughput. Commissioning and science verification observations have already delivered a variety of excellent and deep images that demonstrate its high scientific potential for addressing important astrophysical questions of current interest.

We present HST NICMOS+ACS and Spitzer IRAC+MIPS observations of 41 galaxies at 2

Using deep NIR VLT/ISAAC and optical HST/WFPC2 imaging in the fields of the HDFS and MS1054-03, we study the rest-frame UV-to-optical colors and magnitudes of galaxies to z~3. While there is no evidence for a red sequence at z~3, there does appear to be a well-defined color-magnitude relation (CMR) for blue galaxies at all redshifts, with more luminous galaxies having redder U-V colors. The slope of the blue CMR is independent of redshift d(U-V)/dMV = -0.09 (0.01) and can be explained by a correlation of dust-reddening with luminosity. The average color at fixed luminosity reddens strongly ��(U-V) = 0.75 from z~3 to z=0, much of which can be attributed to aging of the stars. The color scatter of the blue sequence is relatively small sigma(U-V) = 0.25 (0.03) and constant to z~3, but notably asymmetrical with a sharp blue ridge and a wing towards redder colors. We explore sets of star formation histories to study the constraints placed by the shape of the scatter at z=2-3. One particular set of models, episodic star formation, reproduces the detailed properties very well. For a two-state model with high and low star formation, the duty cycle is constrained to be > 40% and the contrast between the states must be a factor > 5 (or a scatter in log(SFR) of > 0.35 dex around the mean). However, episodic models do not explain the observed tail of very red galaxies, primarily Distant Red Galaxies (DRGs), which may have ceased star formation altogether or are more heavily obscured. Finally, the relative number density of red, luminous MV < -20.5 galaxies increases by a factor of ~ 6 from z = 2.7 to z = 0.5, as does their contribution to the total rest-frame V-band luminosity density. We are likely viewing the progressive formation of red, passively evolving galaxies., 29 pages, 24 figures, in emulateapj style. Abstract is abridged. Some postscript figures are compressed. accepted for publication in ApJ (scheduled for August 20, 2007, v665n 2 issue)

Aims. The first star forming galaxies in the early universe should be copious Lya emitters and may play a significant role in ionizing the intergalactic medium (IGM). It has been proposed that the luminosity function of Lya emitting galaxies beyond z ∼ 6 may be used to constrain the neutral fraction of the IGM during this epoch. In this work we report on a search for Lya emitters at redshift 8.8. Methods. We performed a narrow band imaging programme using ISAAC at the ESO VLT. Seven fields, covering a total area of 31 sq. arcmin and for which optical and broad band infra-red images have been obtained in the GOODS survey, were imaged to a limiting flux (respectively luminosity) of -1.3 x 10 -17 erg s -1 cm -2 (respectively ∼1.3 x 10 43 erg s -1 ) in a narrow band filter centered in a region of low OH sky emission at 1.19 μm. Candidate Lya emitters are objects that are detected in the ISAAC NB images and undetected in the visible broad band images. Results. No z = 8.8 Lya emitting galaxies were detected to a limit approaching recent estimates of the luminosity function at z ∼ 6. Our results do suggest, however, that detections or substantial constraints could be achieved by this method in the near future with larger field instruments planned for various telescopes.

The evolution of the line width - luminosity relation for spiral galaxies, the Tully-Fisher relation, strongly constrains galaxy formation and evolution models. At this moment, the kinematics of z > 1 spiral galaxies can only be measured using rest frame optical emission lines associated with star formation, such as Hα and [OIII]5007/4959 and [OII]3727. This method has intrinsic difficulties and uncertainties. Moreover, observations of these lines are challenging for present day telescopes and techniques. Here, we present an overview of the intrinsic and observational challenges and some ways way to circumvent them. We illustrate our results with the HST/NICMOS grism sample data of z ∼ 1.5 starburst galaxies. The number of galaxies we can use in the final Tully-Fisher analysis is only three. We find a ∼2 mag offset from the local rest frame B and R band Tully-Fisher relation for this sample. This offset is partially explained by sample selection effects and sample specifics. Uncertainties in inclination and extinction and the effects of star formation on the luminosity can be accounted for. The largest remaining uncertainty is the line width / rotation curve velocity measurement. We show that high resolution, excellent seeing integral field spectroscopy will improve the situation. However, we note that no flat rotation curves have been observed for galaxies with z > 1. This could be due to the described instrumental and observational limitations, but it might also mean that galaxies at z >1 have not reached the organised motions of the present day.

We present deep 3.6 - 8 micron imaging of the Hubble Deep Field South with IRAC on the Spitzer Space Telescope. We study Distant Red Galaxies (DRGs) at z>2 selected by Js - Ks > 2.3 and compare them to a sample of Lyman Break Galaxies (LBGs) at z=2-3. The observed UV-to-8 micron spectral energy distributions are fit with stellar population models to constrain star formation histories and derive stellar masses. We find that 70% of the DRGs are best described by dust-reddened star forming models and 30% are very well fit with old and ``dead'' models. Using only the I - Ks and Ks - 4.5 micron colors we can effectively separate the two groups. The dead systems are among the most massive at z~2.5 (mean stellar mass = 0.8 x 10^11 Msun) and likely formed most of their stellar mass at z>5. To a limit of 0.5 x 10^11 Msun their number density is ~10 x lower than that of local early-type galaxies. Furthermore, we use the IRAC photometry to derive rest-frame near-infrared J, H, and K fluxes. The DRGs and LBGs together show a large variation (a factor of 6) in the rest-frame K-band mass-to-light ratios (M/L_K), implying that even a Spitzer 8 micron-selected sample would be very different from a mass-selected sample. The average M/L_K of the DRGs is about three times higher than that of the LBGs, and DRGs dominate the high-mass end. The M/L_K ratios and ages of the two samples appear to correlate with derived stellar mass, with the most massive galaxies being the oldest and having the highest mass-to-light ratios, similar as found in the low-redshift universe., Comment: 4 pages, 3 figures, accepted for publication in the ApJ Letters, uses emulateapj

The clustering properties of faint K 2.At the highest redshifts, 2 1.7 reach r_0~8 h^-1 Mpc comoving. This is a factor of 3--4 higher than the correlation length of LBGs with similar number densities, down to V_606 1.7 colors at 2

The composition of ice grains provides an important tool for the study of the molecular environment of star forming regions. Using ISAAC at the VLT to obtain spectra around 4.65 microns we have detected for the first time `XCN' and CO ice in an extragalactic environment: the nuclear region of the nearby dusty starburst/AGN galaxy NGC4945. The profile of the solid CO band reveals the importance of thermal processing of the ice while the prominence of the XCN band attests to the importance of energetic processing of the ice by FUV radiation and/or energetic particles. In analogy to the processing of ices by embedded protostars in our Galaxy, we attribute the processing of the ices in the center of NGC4945 to ongoing massive star formation. Our M-band spectrum also shows strong HI Pfund-beta and H2 0-0 S(9) line emission and gas phase CO absorption lines. The HI, H2, PAH, gas phase CO and the ices seem to be embedded in a rotating molecular disk which is undergoing vigorous star formation. Recently, strong OCN- absorption has been detected in the spectrum of the Galactic center star GC:IRS19. The most likely environment for the OCN- absorption is the strongly UV-exposed GC molecular ring. The presence of processed ice in the center of NGC4945 and our Galactic center leads us to believe that processed ice may be a common characteristic of dense molecular material in star forming galactic nuclei., 9 pages, 8 figures. Accepted for publication in A&A. Also available at this http://www.astro.rug.nl/~spoon/publications.html

We present deep near-infrared (NIR) J(s)-, H-, and K-s-band ISAAC imaging of the Wide Field Planetary Camera 2 (WFPC2) field of the Hubble Deep Field South (HDF-S). The 2.'5 x 2.'5 high Galactic latitude field was observed with the Very Large Telescope under the best seeing conditions, with integration times amounting to 33.6 hr in J(s), 32.3 hr in H, and 35.6 hr in K-s. We reach total AB magnitudes for point sources of 26.8, 26.2, and 26.2, respectively (3sigma), which make it the deepest ground-based NIR observation to date and the deepest K-s-band data in any field. The effective seeing of the co-added images is approximate to0."45 in J(s), approximate to0."48 in H, and approximate to0."46 in K-s. Using published WFPC2 optical data, we constructed a K-s-limited multicolor catalog containing 833 sources down to K-s,AB(tot) less than or similar to 26, of which 624 have seven-band optical-to-NIR photometry. These data allow us to select normal galaxies from their rest-frame optical properties to high redshift (z less than or similar to 4). The observations, data reduction, and properties of the final images are discussed, and we address the detection and photometry procedures that were used in making the catalog. In addition, we present deep number counts, color distributions, and photometric redshifts of the HDF-S galaxies. We find that our faint K-s-band number counts are flatter than published counts in other deep fields, which might reflect cosmic variations or different analysis techniques. Compared to the HDF-N, we find many galaxies with very red V-H colors at photometric redshifts 1.95 < z(phot) < 3.5. These galaxies are bright in K-s, with infrared colors redder than J(s)-K-s > 2. 3 (in Johnson magnitudes). Because they are extremely faint in the observed optical, they would be missed by ultraviolet optical selection techniques, such as the U-dropout method.

The state of the matter that is obscuring a small circumnuclear region in AGN can be probed by observations of its broad emission lines. Infrared lines are particularly useful since they penetrate significant columns of obscuring matter, the properties of which can be constrained by comparing infrared and X-ray obscuration. We report on new 4um spectroscopy of a sample of 12 Seyfert 2 galaxies, probing for broad components to the Brackett alpha 4.05um line. Broad components are observed in 3 to 4 objects. All objects with a broad component exhibit relatively low X-ray obscuring columns, and our results are consistent with a Galactic ratio of 4um obscuration to the BLR and X-ray column. In combination with observations of a NON-Galactic ratio of VISUAL obscuration of BLRs and X-ray obscuring column in Seyferts, and interpreted in a unified AGN scheme, this result can be reconciled with two interpretations. Either the properties of dust near the AGN are modified towards larger grains, for example through coagulation, in a way that significantly flattens the optical/IR extinction curve, or the ratio of dust obscuration to X-ray column varies for different viewing angles with respect to the axis of symmetry of the putative torus. Our spectra also provide a survey of emission in the [SiIX] 3.94um coronal line, finding variation by an order of magnitude in its ratio to Br alpha. The first extragalactic detection of the [CaVII] 4.09um and [CaV] 4.16um coronal lines is reported in the spectrum of the Circinus galaxy., 5 figures. Accepted for publication in A&A

At a redshift of 0.18, Abell 1689 is so far the most distant cluster of galaxies for which substantial mid-infrared (MIR) data have been published. We present here the follow-up optical photometric and spectroscopic observations which were used to study the individual properties of the galaxies members of A1689. Sources with a low [15 micron] / [6.75 micron] flux ratio typically consist of luminous passive early-type galaxies while those with a high MIR color index are mainly luminous, blue, emission-line, morphologically disturbed spirals, i.e. the star-forming galaxies usually associated with the 'Butcher-Oemler' effect. On the other hand, at least 30% of the 15 micron sources have optical counterparts showing no evidence of current star-formation activity, while their 15 micron emission is most likely due to obscured star formation. We argue that the LW3 luminosity measured in the cluster members is a reliable tracer of the total infrared luminosity, L(IR). We derive from L(IR) a star-formation rate free of dust extinction, SFR(IR), which we compare with that determined in the optical from the flux of the [OII] emission line, SFR(opt). The highest total star formation rates (11 Msun/yr) and dust extinction are measured in those galaxies exhibiting in their optical spectrum a signature of a dusty starburst. In contrast, none of the galaxies with post-starburst optical spectra has been detected by ISOCAM. We find a median SFR(IR) of the LW3-detected galaxies of 2 Msun/yr, that is ten times higher than the median SFR(opt) of the [OII] detected galaxies. The ratio SFR(IR)/SFR(opt) is in fact very high, ranging between 10 and 100 for LW3-detected galaxies with [OII] emission. We conclude that a major part, at least 90%, of the star formation activity taking place in Abell 1689 is hidden., 23 pages, 13 figures, A&A in press. A higher resolution version is available at http://www.uni-sw.gwdg.de/~paduc/articles/articles.html

We present low resolution mid infrared spectra of 16 ultraluminous infrared galaxies (ULIRGs) obtained with the CVF spectroscopy mode of ISOCAM on board the Infrared Space Observatory ISO. Our sample completes previous ISO spectroscopy of ultra- and hyperluminous infrared galaxies towards higher luminosities. The combined samples cover an infrared luminosity range of \~10^{12 -13.1} Lo. For about half of the high luminosity ULIRGs studied here, strong aromatic emission bands suggest starburst dominance. Other spectra are dominated by a strong AGN-related continuum with weak superposed emission features of uncertain nature. An improved method to quantitatively characterize the relative contribution of star formation and AGN activity to the mid-infrared emission of ULIRGs is presented. As dominant source of the bolometric luminosity, starbursts prevail at the lower end and AGNs at the higher end of this range. The transition between mostly starburst and mostly AGN powered occurs at ~10^{12.4}$ to $10^{12.5} Lo, and individual luminous starbursts are found up to ~10^{12.65} Lo., Comment: Accepted for publication in ApJ, 42 pages, 13 figures, 5 tables

Spectroscopy from the Infrared Space Observatory ISO has for the first timeprovided the sensitivity to exploit the diagnostic power ofmid-infrared fine structure lines and PAH features for the study ofultraluminous infrared galaxies (LIR >1012 L ⊙). We report on observations obtainedwith SWS, ISOPHOT-S, and the CVF option of ISOCAM. From both fine structure lines and PAH features, we find that the majority of ULIRGs is predominantlypowered by star formation. Our total sample of about 75 ULIRGs allows tosearch for trends within the class of ULIRGs: The fraction of AGNs increaseswith luminosity above ∼ 3 × 1012L⊙ but there is no obvioustrend for ULIRGs to be more AGN-like with more advanced merger phase.

The deepest survey for Hα emitting galaxies at z ≃ 2.2has recently been made in narrow-band (≃ 1%) filters around2.1μm using SOFI at the ESO NTT telescope. An effective area of≃ 100 sq. arcmin and a comoving volume of 9000 Mpc3 (forH0 = 50, q0 = 0.5) has been covered to a volume weighted 3σ line flux limit of ≃ 5 × 10-17 erg s-1cm-2. Our survey covered the WFPC2 and STIS fields in the HubbleDeep Field South and an anonymous field about 30 deg. away. Thefaintest limit reached was 3 × 10-17 erg s-1 cm-2 onthe WFPC2 field. In total, 10 convincing candidates with deduced starformation rates in the range 9 - 50 M⊙/yr and an equal number ofmarginal ones have been identified for confirmation and follow-upspectroscopy with ISAAC at the VLT. Based on a very preliminaryanalysis we compare our results with those of earlier surveys andbriefly discuss some possible implications for the form of theevolution out to z ≃ 2 and the effects of clustering.

We present an ISO SWS and ISOPHOT-S, mid-infrared spectroscopic survey of 15 ultra-luminous IRAS galaxies. We combine the survey results with a detailed case study, based on near-IR and mm imaging spectroscopy, of one of the sample galaxies (UGC 5101). We compare the near- and mid-IR characteristics of these ultra-luminous galaxies to ISO and literature data of thirty starburst and active galactic nuclei (AGN), template galaxies. We find that 1) 70-80% of the ultra-luminous IRAS galaxies in our sample are predominantly powered by recently formed massive stars. 20-30% are powered by a central AGN. These conclusions are based on a new infrared 'diagnostic diagram' involving the ratio of high to low excitation mid-IR emission lines on the one hand, and on the strength of the 7.7um PAH feature on the other hand. 2) at least half of the sources probably have simultaneously an active nucleus and starburst activity in a 1-2 kpc diameter circum-nuclear disk/ring. 3) the mid-infrared emitting regions are highly obscured. After correction for these extinctions, we estimate that the star forming regions in ULIRGs have ages between 10^7 and 10^8 years, similar to but somewhat larger than those found in lower luminosity starburst galaxies. 4) in the sample we have studied there is no obvious trend for the AGN component to dominate in the most compact, and thus most advanced mergers. Instead, at any given time during the merger evolution, the time dependent compression of the circum-nuclear interstellar gas, the accretion rate onto the central black hole and the associated radiation efficiency may determine whether star formation or AGN activity dominates the luminosity of the system., Comment: 63 pages postscript (ex. MS Word), 11 postscript and 2 gif figures, submitted to ApJ. See also http://www.mpe-garching.mpg.de/ISO/preprint/MPE-IR-97003.html

We discuss 2.5–45 µm spectra of the Circinus galaxy and of Cen A, obtained with the Short Wavelength Spectrometer (SWS) on board the Infrared Space Observatory. The large number of detected ionic fine structure lines, observable also in visually obscured sources, provides strong constraints on the shape of the ionizing spectrum, which is found to exhibit a UV bump peaking at ~ 70 eV in the case of Circinus. Pure rotational emission of molecular hydrogen, directly probing warm molecular gas, can for the first time be detected in external galaxies.

We present a first analysis of 2.4-45µm spectra of NGC 1068 obtained with the Short Wavelength Spectrometer SWS on board the Infrared Space Observatory ISO. The measured fine-structure line fluxes can be fit successfully by a simple photoionization model invoking an EUV bump in the ionizing continuum, similar to the case of the Circinus galaxy. Difference are observed between the [OIV] 26µm NLR line profile and optical NLR line profiles which may indicate significant extinction to part of the NLR. We detect pure rotational transitions of molecular hydrogen that must be emitted by molecular gas spanning a wide range of temperatures. The unusual strength of the fundamental S(0) 28µm rotational transition is evidence for a large (> 1.5 × 109 M⊙) gas mass at temperatures nea r 100 K. Either most of the gas in the circumnuclear region of NGC 1068 is warm or previous molecular mass estimates based on CO observations were too low. Strong mid-infrared continuum from the circumnuclear warm dust is prominent in our spectrum. The weak PAH emission detected at the edges of the 9.7µm silicate absorption should be considered in interpretations of the silicate feature.

This paper gives an overview of infrared array detectors which have been tested and used at ESO. The performance of arrays using Reticon type readouts, CCD readouts and switched FET multiplexers have been evaluated for both InSb and Hg1−xCdxTe detectors. Performance limitations specific to the NICMOS3 256 × 256 Hg1−xCdxTe detector installed in the ESO infrared array camera IRAC2 are addressed. The first test results with a high well capacity SBRC 256 × 256 InSb array are also presented.Advanced readout techniques for image sharpening tested on a 2.2-m telescope are discussed briefly. A new generation of instruments being built for the VLT, the very large telescope project of ESO, is designed to house large format 1024 × 1024 IR arrays. A fast data acquisition system is currently being developed at ESO. The system is capable of handling the high data rates generated in the thermal infrared by large format low well capacity arrays. It can also cope with the low read noise required for flux levels of ≤ one photon/sec. It will first be installed in ISAAC, the Infrared Array Camera and Spectrometer built for the VLT (Moorwood 1993). The present status of both the detector developments and the data acquisition system is reviewed.

Many galaxies are thought to have supermassive black holes at their centres-more than a million times the mass of the Sun. Measurements of stellar velocities and the discovery of variable X-ray emission have provided strong evidence in favour of such a black hole at the centre of the Milky Way, but have hitherto been unable to rule out conclusively the presence of alternative concentrations of mass. Here we report ten years of high-resolution astrometric imaging that allows us to trace two-thirds of the orbit of the star currently closest to the compact radio source (and massive black-hole candidate) Sagittarius A*. The observations, which include both pericentre and apocentre passages, show that the star is on a bound, highly elliptical keplerian orbit around Sgr A*, with an orbital period of 15.2 years and a pericentre distance of only 17 light hours. The orbit with the best fit to the observations requires a central point mass of (3.7 +/- 1.5) x 10(6) solar masses (M(*)). The data no longer allow for a central mass composed of a dense cluster of dark stellar objects or a ball of massive, degenerate fermions.

Astronomical measurements at mid- and far-infrared wavelengths can be made by using aircraft or balloons to carry telescopes above the strongly absorbing lower atmosphere. To measure the atmospheric background radiation present at these altitudes, a Michelson interferometer has been built and flown to a height of 38 km on a balloon. This paper describes the instrument and the methods of data reduction and calibration, and presents initial spectra in the range 100-1000 cm(-1) (10-100 micro) obtained to a mean resolution of 34 cm(-1) during flight.

VLT Science Highlights.- VLT Science Highlights.- Pushing the VLT Spectroscopy of Distant Galaxies to the Limits and Future Prospects.- Pushing FORS to the Limit-A New Population of Faint Extended Ly? Emitters at z?3.- VIMOS Integral Field Spectroscopy of Gaseous Nebulae in Local Group Dwarf Galaxies.- Near IR Integral Field Spectroscopy of a Nearby Starburst.- The ESO Large Programme "First Stars".- The Contribution of UVES@VLT to the New Era of QSO Absorption Line Studies.- IMAGES: A Unique View of the Galaxy Mass Assembly Since z=1.- The Metallicity Evolution at High Redshift.- Near-IR Spectroscopy of Blue Supergiants.- Integral Field Spectroscopy of Protoplanetary Disks in Orion with VLT FLAMES.- MAD@VLT: Deep into the Madding Crowd of Omega Centauri.- Chemical Evolution of the Galaxy and Supernova Yields after UVES.- VLTI Science Highlights.- VLTI Science Highlights.- MIDI Sees Active Galactic Nuclei.- The Use of the VLTI for Studying the Asymmetric Mass Loss of Evolved Stars.- Mid-infrared Interferometric Observations of Young Circumstellar Discs.- VLTI-AMBER Observations of ? Carinae with High Spatial Resolution and Spectral Resolutions of ?/??=1500 and 12?000*.- Resolving the Inner Active Accretion Disk Around the Herbig Be Star MWC 147 with VLTI/MIDI?+?AMBER Spectro-interferometry.- Multi-epoch VLTI/MIDI Observations of the Carbon-rich Mira Star V Oph.- A Mid-infrared Interferometric Study of the Circumstellar Environment of Dusty OH/IR Stars with VLTI/MIDI.- The Closest Dusty Cloud Ever Detected Around a R CrB Variable Star Using the VLTI/MIDI Instrument.- Future VLT and VLTI Science Priorities.- A Twenty Year Science Vision for European Astronomy.- Baryonic Acoustic Oscillations.- Galaxy Formation and Evolution.- Exoplanets: The Road to Earth Twins.- Next Generation Deep Redshift Surveys with the VLT.- GUAIX: The UCM Group of Extragalactic Astrophysics and Astronomical Instrumentation.- VISTA Public Surveys and VLT followup.- Probing Dark Energy with Cosmological Redshift Surveys at the VLT.- The First Galaxies and Galaxy Clusters.- Narrow Band Surveys and the Epoch of Reionization.- Stellar Archaeology and Galaxy Genesis: The Need for Large Area Multi-Object Spectrograph on 8 m-Class Telescopes.- Near-field Cosmology with the VLT.- Chemical Evolution of Local Group Galaxies.- The VLTI as a Tool to Study Eclipsing Binaries for an Improved Distance Scale.- VLT and VLTI Synergy with ELTs.- Status of the European ELT.- The Science Case for the European ELT.- GRB Afterglows in the ELT Era.- On the Way to an E-ELT Instrumentation Plan.- From ESPRESSO to CODEX.- First Results of AQuEye, a Precursor 'Quantum' Instrument for the E-ELT.- The E-ELT: A Chance to Measure Cosmic Magnetic Fields.- The Experience from VISIR and the Design of an ELT Mid-infrared Instrument.- HARMONI: A Narrow Field Near-infrared Integral Field Spectrograph for the E-ELT.- Which Synergies Between LBT/LINC Nirvana and Future ELTs?.- TMT Science and Instruments.- VLT Synergies with ALMA and JWST.- The Atacama Large Millimeter/Submillimeter Array.- Observational Cosmology with the ELT and JWST.- Integral Field Spectroscopy of (U)LIRGs. From VLT to JWST.- Second Generation VLT and VLTI Instrument Programme.- VLT and VLTI Second Generation Instrument Overview and Resources.- HAWK-I and Infrared Imaging on the VLT.- X-Shooter: A Medium-resolution, Wide-Band Spectrograph for the VLT.- KMOS and KMOS++.- New Science Opportunities Offered by MUSE.- SPHERE: A 'Planet Finder' Instrument for the VLT.- Milli-arcsecond Astrophysics with VSI, the VLTI Spectro-imager in the ELT Era.- Prospects for Near-infrared Characterisation of Hot Jupiters with the VLTI Spectro-imager (VSI).- MATISSE.- MATISSE Science Cases.- GRAVITY: Microarcsecond Astrometry and Deep Interferometric Imaging with the VLT.- New Instrument Concepts and VLT/I Operating Modes.- Smart Focal Plane Technologies for VLT Instruments.- Applications of Digital Micromirror Devices to Astronomical Instrumentation.- FORS in the Era of Second Generation VLT Instrumentation.- Wide Field Options on the VLT.- A Few Degrees Very Wide Field of View Camera for VLT as a Finder for ELT.- Science with a 16 m VLT: The Case for Variability of Fundamental Constants.- ESPRESSO: A High Resolution Spectrograph for the Combined Coude Focus of the VLT.- Feeding Optics for the ESPRESSO Spectrograph.- New Design Approach for a Very-High Resolution Spectrograph for the VLT Combined Focus.- ESPRESSO Optomechanics.- ESPRESSO Science Software.- High Resolution Wavelength Calibration: Advancements with the Laser Frequency Comb Development.- Precision Radial Velocities in the Infrared.- Very Large Spectroscopic Surveys with the VLT.- New Developments in Integral Field Spectroscopy.- ULTRAPHOT.- Super-GIRAFFE: The Next Generation High Multiplex Optical Spectrograph with d-IFUs.- FLEX (The First Light Explorer)-Carinae with High Spatial Resolution and Spectral Resolutions of ?/??=1500 and 12?000*.- Resolving the Inner Active Accretion Disk Around the Herbig Be Star MWC 147 with VLTI/MIDI?+?AMBER Spectro-interferometry.- Multi-epoch VLTI/MIDI Observations of the Carbon-rich Mira Star V Oph.- A Mid-infrared Interferometric Study of the Circumstellar Environment of Dusty OH/IR Stars with VLTI/MIDI.- The Closest Dusty Cloud Ever Detected Around a R CrB Variable Star Using the VLTI/MIDI Instrument.- Future VLT and VLTI Science Priorities.- A Twenty Year Science Vision for European Astronomy.- Baryonic Acoustic Oscillations.- Galaxy Formation and Evolution.- Exoplanets: The Road to Earth Twins.- Next Generation Deep Redshift Surveys with the VLT.- GUAIX: The UCM Group of Extragalactic Astrophysics and Astronomical Instrumentation.- VISTA Public Surveys and VLT followup.- Probing Dark Energy with Cosmological Redshift Surveys at the VLT.- The First Galaxies and Galaxy Clusters.- Narrow Band Surveys and the Epoch of Reionization.- Stellar Archaeology and Galaxy Genesis: The Need for Large Area Multi-Object Spectrograph on 8 m-Class Telescopes.- Near-field Cosmology with the VLT.- Chemical Evolution of Local Group Galaxies.- The VLTI as a Tool to Study Eclipsing Binaries for an Improved Distance Scale.- VLT and VLTI Synergy with ELTs.- Status of the European ELT.- The Science Case for the European ELT.- GRB Afterglows in the ELT Era.- On the Way to an E-ELT Instrumentation Plan.- From ESPRESSO to CODEX.- First Results of AQuEye, a Precursor 'Quantum' Instrument for the E-ELT.- The E-ELT: A Chance to Measure Cosmic Magnetic Fields.- The Experience from VISIR and the Design of an ELT Mid-infrared Instrument.- HARMONI: A Narrow Field Near-infrared Integral Field Spectrograph for the E-ELT.- Which Synergies Between LBT/LINC Nirvana and Future ELTs?.- TMT Science and Instruments.- VLT Synergies with ALMA and JWST.- The Atacama Large Millimeter/Submillimeter Array.- Observational Cosmology with the ELT and JWST.- Integral Field Spectroscopy of (U)LIRGs. From VLT to JWST.- Second Generation VLT and VLTI Instrument Programme.- VLT and VLTI Second Generation Instrument Overview and Resources.- HAWK-I and Infrared Imaging on the VLT.- X-Shooter: A Medium-resolution, Wide-Band Spectrograph for the VLT.- KMOS and KMOS++.- New Science Opportunities Offered by MUSE.- SPHERE: A 'Planet Finder' Instrument for the VLT.- Milli-arcsecond Astrophysics with VSI, the VLTI Spectro-imager in the ELT Era.- Prospects for Near-infrared Characterisation of Hot Jupiters with the VLTI Spectro-imager (VSI).- MATISSE.- MATISSE Science Cases.- GRAVITY: Microarcsecond Astrometry and Deep Interferometric Imaging with the VLT.- New Instrument Concepts and VLT/I Operating Modes.- Smart Focal Plane Technologies for VLT Instruments.- Applications of Digital Micromirror Devices to Astronomical Instrumentation.- FORS in the Era of Second Generation VLT Instrumentation.- Wide Field Options on the VLT.- A Few Degrees Very Wide Field of View Camera for VLT as a Finder for ELT.- Science with a 16 m VLT: The Case for Variability of Fundamental Constants.- ESPRESSO: A High Resolution Spectrograph for the Combined Coude Focus of the VLT.- Feeding Optics for the ESPRESSO Spectrograph.- New Design Approach for a Very-High Resolution Spectrograph for the VLT Combined Focus.- ESPRESSO Optomechanics.- ESPRESSO Science Software.- High Resolution Wavelength Calibration: Advancements with the Laser Frequency Comb Development.- Precision Radial Velocities in the Infrared.- Very Large Spectroscopic Surveys with the VLT.- New Developments in Integral Field Spectroscopy.- ULTRAPHOT.- Super-GIRAFFE: The Next Generation High Multiplex Optical Spectrograph with d-IFUs.- FLEX (The First Light Explorer)-The Science Case for a Fully OH Suppressed IFU Spectrograph.- An N-Band Integral Field Spectrometer Survey Instrument for the VLT.- High Resolution Visible Imaging on the VLT.- Life on the Fast Lane: The Burst Mode at the VLT at Present and in the Future.- High Resolution Near Infrared Spectroscopy: Prospects for 10 and 40 m Class Telescopes.- Prospects and Needs of Micro-arcsecond Astrometry.- CASIS: Cassegrain Adaptive-Optics Simultaneous Imaging System for the VLT.- The Need for a General Purpose Diffraction Limited Imager at the VLT.- Exploring the Time Axis-High Resolution Timing Observations with Present and Future Instrumentation.- Advanced Calibration for Quantitative Astrophysics: 2nd Generation VLT Instruments and Beyond.- Quantitative Near-IR Spectroscopy of OB Stars.- The Very Large Telescope Interferometer in the ELT Era.- VLTI and Beyond: The Next Steps in AGN Research with Interferometers.

The instrumentation plan for the ESO VLT has been approved in March 1990: it includes 10 instruments, two of which are to be replicated, distributed among the Nasmyth, Cassegrain and coude focii of the four unit telescopes of the VLT and the incoherently combined focus. The instruments will be used for a variety of observations in the wavelength range from the UV atmospheric cutoff to around 20 mu m. Conceptual designs are presented for a medium resolution IR spectrometer/imager, Ia focal reducer/low dispersion spectrograph, an echelle spectrograph, a multi-fibre spectrograph and an 8-14 mu m imager/spectrometer. Design requirements and expected capabilities are given for an high resolution infrared camera and for a speckle camera, planned to operate in combination with the telescope adaptive optics systems. These first seven instruments are expected to come into operation within a period of around 2 years beginning in 1996. The current design options for the high spectral resolution spectrometers for the UV-visual and the infrared region are also presented.

All the ISO instruments are contributing to the study of activity in galaxies of essentially all types. Although AGN's as such are pointlike, the beautiful CAM image of CenA shown by Catherine Cesarsky has given us the clearest view so far of its visually obscured nucleus and surrounding spiral disc embedded in an elliptical galaxy. The CAM CVF is also providing spectral images of the PAH features and important diagnostic ionic lines (e.g [NeII] and [NeIII]) in the circumnuclar regions of AGN and merging starburst systems (Vigroux et al., 1996). PHT is providing detailed spectral energy distributions over the complete 2.5-240µm range and PHTS is proving invaluable for assembling a catalogue of low resolution (R ⋍ 90) galaxy spectra covering the 6-12µm PAH features. SWS and LWS are generating higher resolution (R ⋍ 2000-200) spectra over the range 2.5-200µm such as that shown in Fig. 1. of the Circinus galaxy which exhibits both AGN and starburst activity and well illustrates the wide range of diagnostic features, many seen for the first time, accessible to ISO studies of galaxies. It shows the overall continuum with a peak around 100µm; PAH features and Si absorption which dominate the spectrum around 10µm; H recombination lines; H2 pure rotational emission lines; low ionization potential ionic lines excited by starburst activity and high excitation lines (up to ⋍ 300eV) excited by the visually obscured AGN.

Clusters of galaxies as gravitational lenses allow to study the stellar content and properties of high-z galaxies much fainter than the usual spectroscopic field surveys. We review the recent results obtained on the identification and study of very distant galaxies seen through lensing clusters. Using the gravitational amplification effect in lenses with well known mass distributions, it is possible to build up and study a sample of galaxies with 1 ∼ z ∼ 2 was the spectacular blue arc in Cl2244-02 ([10]). Recent examples of highly magnified galaxies, identified either purposely or serendipitously, strongly encourages this approach: the star-forming source #384 in A2218, at z=2.51 ([4]), the luminous z=2.7 galaxy behind MS1512+36 ([17]), three z ∼ 4 galaxies in Cl0939+47 ([16]), a z=4.92 system in Cl1358+62 ([7], [14]), the z=2.72 arc behind MS1512+36 ([13]), and the two red galaxies at z ∼ 4 in A2390 ([8], [12]). We present the 0 In collaboration with : B. Fort (IAP, F), J.-P. Kneib (OMP, F), J.-F. Le Borgne (OMP, F), Y. Mellier (IAP, F), I. Appenzeller (Obs. Heidelberg, D), R. Bender (Munich Observatory, D), L. Campusano (U. Chile, Chile), M. Dantel-Fort (O. Paris, F), R.S. Ellis (IoA, UK) A. Moorwood (ESO, D), S. Seitz (Munich Observatory, D)

We present a study of the submillimeter (submm) emission of Distant Red Galaxies (DRGs). The DRGs are selected by the criterion (J-K)>2.3, and are generally massive galaxies at redshifts higher than 2, with red rest-frame optical colors. Using a deep SCUBA submm image of a field centred on the cluster MS1054-03, we obtain a statistical detection of the DRGs at redshift z=2-3.5, with an average 850um flux density of 1.11+-0.28mJy. The detection implies an average star formation rate (SFR) of 127+-34 M_sun/yr (lensing corrected), assuming that the far-infrared (FIR) spectral energy distribution (SED) is well-described by a modified blackbody. The SFR derived from the submm agrees well with SFRs derived from SED fitting of optical-near-infrared data and average X-ray emission. Constant Star Formation models imply ages of 2Gyr, extinction A_V=2.4 mag, which is consistent with the FIR to rest-frame optical luminosity ratio of ~15. DRGs are older and have lower SFRs relative to optical luminosity than (ultra-)luminous infrared galaxies, although their FIR luminosities are similar. The DRGs at 24) at 1, Comment: 4 pages, including 1 figure; accepted by ApJ Letters

We present deep near-infrared Js, H, and Ks band imaging of a field around MS1054-03, a massive cluster at z=0.83. The observations were carried out with ISAAC at the ESO VLT as part of the Faint InfraRed Extragalactic Survey (FIRES). The total integration time amounts to 25.9h in Js, 24.4h in H, and 26.5h in Ks, divided nearly equally between four pointings covering 5.5'x5.3'. The 3-sigma total limiting AB magnitudes for point sources from the shallowest to deepest pointing are Js=26.0-26.2, H=25.5-25.8, and Ks=25.3-25.7. The effective spatial resolution of the coadded images has FWHM=0.48", 0.46", and 0.52" in Js, H, and Ks. We complemented the ISAAC data with deep optical imaging using existing HST WFPC2 mosaics in the F606W and F814W filters and new U, B and V band data from VLT FORS1. We constructed a Ks-band limited multicolour source catalogue to Ks(total,AB)=25 (about 5-sigma for point sources). The catalogue contains 1858 objects, of which 1663 have eight-band photometry. We describe the observations, data reduction, source detection and photometric measurements method. We present the number counts, colour distributions, and photometric redshifts z_ph of the catalogue sources. We find that our counts at the faint end 22=0.078. The MS1054-03 field observations complement our HDF-South data set with nearly five times larger area at about 0.7 brighter magnitudes. [ABRIDGED], Comment: Accepted for publication in the Astronomical Journal. 32 pages, 14 b/w figures, 1 color figure

(ABRIDGED) We have undertaken a programme of 3 micron narrowband imaging of a sample of nearby template galaxies covering a wide range of metallicity, star formation activity, and nuclear activity. In the present paper we present first results: high spatial resolution images of PAH emission and the adjacent continuum emission from the central regions of the nearby starburst galaxies NGC253 and NGC1808. Globally, the PAH emission is seen to peak on the central starburst regions of both sources. On smaller scales, however, we see no general spatial correlation or anti-correlation between the PAH emission and the location of sites of recent star formation, suggesting that the degree to which PAH emission traces starburst activity is more complicated than previously hypothesized based on results from data with lower spatial resolution. We do find spatial correlations, though, when we consider the PAH-to-continuum ratio, which is low at the positions of known super star clusters in NGC1808 as well as at the position of the IR peak in NGC253. We take this to imply a decrease in the efficiency of PAH emission induced by the star formation, caused by mechanical energy input into the ISM or photoionisation or photodissociation of the PAH molecules. All three hypotheses are discussed. In addition, for the first time we present observations of PAH emission in the superwind of a starbursting system (NGC253), providing strong support that winds are heavily mass-loaded and entrain substantial amounts of ambient ISM. We have also found a plausible connection between observed NaD absorption, H2, and PAHs above the plane of NGC253. This observation has important implications for enriching galaxy halos and possibly the intergalactic medium with small dust grains., Comment: A&A Accepted, for a version with higher quality figures see http://www.eso.org/~ltacconi/PAPERS

Using deep near-infrared imaging of the Hubble Deep Field South with ISAAC on the Very Large Telescope we find 6 large disk-like galaxies at redshifts z = 1.4-3.0. The galaxies, selected in K_s (2.2 micron), are regular and surprisingly large in the near-infrared (rest-frame optical), with face-on effective radii r_e = 0.65"-0.9" or 5.0-7.5 h_70^-1 kpc in a Lambda-CDM cosmology, comparable to the Milky Way. The surface brightness profiles are consistent with an exponential law over 2-3 effective radii. The WFPC2 morphologies in Hubble Space Telescope imaging (rest-frame UV) are irregular and show complex aggregates of star-forming regions ~2" (~15 h_70^-1 kpc) across, symmetrically distributed around the K_s-band centers. The spectral energy distributions show clear breaks in the rest-frame optical. The breaks are strongest in the central regions of the galaxies, and can be identified as the age-sensitive Balmer/4000 Angstrom break. The most straightforward interpretation is that these galaxies are large disk galaxies; deep NIR data are indispensable for this classification. The candidate disks constitute 50% of galaxies with L_V > 6 x 10^10 h_70^-2 L_sun at z = 1.4-3.0. This discovery was not expected on the basis of previously studied samples. In particular, the Hubble Deep Field North is deficient in large galaxies with the morphologies and profiles we report here., LaTeX, 5 pages, 2 figures, 1 table. Accepted for publication in the Astrophysical Journal Letters

We have re-analyzed the 6-12 micron ISO spectrum of the ultra-luminous infrared galaxy Arp220 with the conclusion that it is not consistent with that of a scaled up version of a typical starburst. Instead, both template fitting with spectra of the galaxies NGC4418 and M83 and with dust models suggest that it is best represented by combinations of a typical starburst component, exhibiting PAH emission features, and a heavily absorbed dust continuum which contributes ~40% of the 6-12 micron flux and likely dominates the luminosity. Of particular significance relative to previous studies of Arp220 is the fact that the emission feature at 7.7 micron comprises both PAH emission and a broader component resulting from ice and silicate absorption against a heavily absorbed continuum. Extinction to the PAH emitting source, however, appears to be relatively low. We tentatively associate the PAH emitting and heavily dust/ice absorbed components with the diffuse emission region and the two compact nuclei respectively identified by Soifer et al. (2002) in their higher spatial resolution 10 micron study. Both the similarity of the absorbed continuum with that of the embedded Galactic protostars and results of the dust models imply that the embedded source(s) in Arp220 could be powered by, albeit extremely dense, starburst activity. Due to the high extinction, it is not possible with the available data to exclude that AGN(s) also contribute some or all of the observed luminosity. In this case, however, the upper limit measured for its hard X-ray emission would require Arp220 to be the most highly obscured AGN known., Comment: 11 pages, 9 figures. Accepted for publication in A&A. Also available at http://www.astro.rug.nl/~spoon/publications.html

The FORS Deep Field project is a multi-colour, multi-object spectroscopic investigation of an approx. 7 times 7 region near the south galactic pole based mostly on observations carried out with the FORS instruments attached to the VLT telescopes. It includes the QSO Q 0103-260 (z = 3.36). The goal of this study is to improve our understanding of the formation and evolution of galaxies in the young Universe. In this paper the field selection, the photometric observations, and the data reduction are described. The source detection and photometry of objects in the FORS Deep Field is discussed in detail. A combined B and I selected UBgRIJKs photometric catalog of 8753 objects in the FDF is presented and its properties are briefly discussed. The formal 50% completeness limits for point sources, derived from the co-added images, are 25.64, 27.69, 26.86, 26.68, 26.37, 23.60 and 21.57 in U, B, g, R, I, J and Ks (Vega-system), respectively. A comparison of the number counts in the FORS Deep Field to those derived in other deep field surveys shows very good agreement., Comment: 15 pages, 11 figures (included), accepted for publication in A&A

The FIRBACK (Far Infrared BACKground) survey is one of the deepest imaging surveys carried out at 170 microns with ISOPHOT onboard ISO, and is aimed at the study of the structure of the Cosmic Far Infrared Background. This paper provides the analysis of resolved sources. After a validated process of data reduction and calibration, we perform intensive simulations to optimize the source extraction, measure the confusion noise (sigma_c = 45 mJy), and give the photometric and astrometric accuracies. 196 galaxies with flux S > 3 sigma_c are detected in the area of 3.89 square degrees. Counts of sources with flux S > 4 sigma_c present a steep slope of 3.3 +/- 0.6 on a differential "logN-logS" plot between 180 and 500 mJy. As a consequence, the confusion level is high and will impact dramatically on future IR deep surveys. This strong evolution, compared with a slope of 2.5 from Euclidian geometry, is in line with models implying a strongly evolving Luminous Infrared Galaxy population. The resolved sources account for less than 10% of the Cosmic Infrared Background at 170 microns, which is expected to be resolved into sources in the 1 to 10 mJy range., Accepted for publication in A&A. 16 pages, includes new aa.cls. Tables 7 to 13 included here will appear on the electronic version of A&A and at the CDS. Paper, catalog and images (with better quality) also available at http://wwwfirback.ias.u-psud.fr and http://mips.as.arizona.edu/~hdole/firback

We have obtained ISOPHOT-S low resolution mid-infrared spectra of a sample of 60 Ultraluminous Infrared Galaxies (ULIRGs). We use the strength of the 'PAH' mid-infrared features as a discriminator between starburst and AGN activity, and to probe for evolutionary effects. Observed ratios of PAH features in ULIRGs differ slightly from those in lower luminosity starbursts. We suggest that such PAH ratio changes relate to the conditions in the interstellar medium in these galaxies, and in particular to extinction. (C)1999 COSPAR. Published by Elsevier Science Ltd.

ISO spectra1 of the supernova remnant RCW103 are presented. This object is the prototype of a SNR shock heavily interacting with dense ISM (probably a molecular cloud). The spectra are dominated by prominent lines and show very little continuum at » < 40 µm suggesting that the 12 and 25 µm IRAS emission from these types of remnant could be dominated by lines rather than continuum emission from warm dust heated by the shock as generally believed. The ISO data provide for the first time a simple and reliable estimate of the gas phase abundances of Si and Fe which are found to be close to solar relative to non refractory species such as Ne, S and Ar. This indicates that the shock is very effective in destroying the ISM dust and may therefore explain the absence of warm dust behind the shock. Like the optical Nickel lines, [NiII]6.63 µm yields Ni/Fe abundances a factor ≥10 above solar which we conclude results from a large underestimation of the computed Ni+ collision strengths.

Emission-line searches for high-z starburst galaxies carried out to date have mostly targeted the Lya line. The remarkable lack of success of these searches (Thompson et al. 1995, Thompson & Djorgovski 1995) is most likely a result of absorption by dust, which, even if present in only small amounts, will strongly suppress the resonantly scattered Lya emission. Indeed, most of the high red-shift starburst galaxies recently identified by Steidel et al. (1996) have no Lya emission. Dust absorption is largely avoided by searching for Ha in stead of Lya. Here we report the first results of a new large-area survey for Ha emission at z = 2.2–2.4.

We present high spatial resolution near-infrared imaging of the nuclear region of the starburst galaxy NGC 1808. The continuum emission is smooth throughout the circumnuclear region and shows no morphological change with wavelength. Most of the continuum is produced by the evolved bulge population, while red supergiants and hot dust only make a small contribution. The circumnuclear line emission arises from hot spots in a ring-like structure. From comparison of Brγ and Ha fluxes, we derive extinctions between A V of 3 and 5 towards the hot spots. From analysis of the line and continuum luminosities, using an evolutionary starburst model, we derive for each hot spot star formation rate 0.1–0.6 M⊙ yr-1 and supernova rate 0.4–11 × 10-3 yr-1. The age of the burst is between 8 and 17 Myr in the circumnuclear region, but much older, ~40 Myr, in the nucleus. The line ratios of the nucleus are similar to Seyfert nuclei, and the multiwavelength evidence for and against hidden Seyfert activity in NGC 1808 is discussed.

This paper gives an overview of infrared array detectors which have been tested and used at ESO. The performance of arrays using Reticon type readouts, CCD readouts and switched FET multiplexers have been evaluated for both InSb and Hg1-xCdxTe detectors. Performance limitations specific to the NICMOS3 256 x 256 Hg1-xCdxTe detector installed in the ESO infrared array camera IRAC2 are addressed. The first test results with a high well capacity SBRC 256 x 256 InSb array are also presented.

Infrared spectra of selected stellar absorption features (CO 2.29, 1.62 and Si 1.59 μm) of a sample of Seyferts and many calibrators (stellar clusters, normal galaxies and well known starbursters) are presented. For HII and Seyferts we also report Brγ measurements.

Spectra of several galactic and LMC supernova remnants have been obtained at R ~ 1500 in the 1−2.5 µm region with the cooled grating/array spectrometer, IRSPEC, on the ESO 3.6m telescope. The brightest lines observed are from [FeII]. In RCW 103, which exhibits the highest surface brightness, H (Brγ at 2.17µm) and H2 (1−0 S(1) at 2.12µm) lines have also been detected. A good correlation is found between [FeII] (1.64µm) and Hβ implying similar ionization structures and Fe abundances in a wide variety of remnants. The actual [FeII](1.64µm)/Hβ ratio of ~0.2 also implies a high depletion factor (>0.9) for Fe. Electron densities, extinctions and [FeII] luminosities derived from these data are presented and discussed and attention drawn to a potentially interesting discrepancy between H(Brγ) and Hβ fluxes.

A high resolution (λ/Δλ~104 Michelson interferometer has been used on NASA’s AIRO (C-141) telescope in November-December 1975 to observe far infrared emission lines from HII regions. The instrument operates in the rapid scanning mode under computer control and high resolution spectra are computed, averaged and displayed on-line. Observations were made in the range 17.5–20µm and 70–100 µm, with spectral resolutions of 0.03 and 0.02 cm-1 respectively, on the Orion Nebula and Jupiter. Emission spectra of the stratosphere were also obtained in these wavelength ranges. Emission from SIII at 18.7µ has been detected in the Orion Nebula. The intensity of this line is discussed compared with theoretical predictions. Preliminary results concerning the observations of OIII (88µ) in the Orion Nebula are also presented.

ESA is currently conducting the Phase A study of a large infrared telescope for Spacelab. The preliminary design of a 2.8 m aperture, modified Ritchey-Chretien telescope can be accommodated in the short module or pallet only Spacelab configurations. Pointing is by means of the Instrument Pointing System. The facility has outstanding potential for a wide range of astronomical observations in the far infrared.