The requirements on ELTs from the perspective of X-ray astronomy are explored. These requirements will be driven largely by deep X-ray surveys, like those conducted with XMM-Newton and the Chandra X-ray Observatory. Up to the present time, ground-based telescopes have largely kept abreast of the needs arising from deep X-ray surveys, i.e. the current generation of 10m-class telescopes is able to (barely) match the required spectroscopic needs for optical identifications in most cases (up to 70%). There are two X-ray astronomy facilities currently proposed and under study: the European-led X-ray Early Universe Spectroscopic mission (XEUS) and the NASA proposal Constellation-X. The emphasis of both these missions, like XMM-Newton, is X-ray spectroscopy, but they will both perform deep surveys which will need optical follow-up spectroscopy towards the middle or end of the next decade.

Although it is presently not possible to extract the true composition of a comet nucleus from its coma composition, the distribution of physical and chemical coma properties among comets may be expedient to establish a comet classification scheme that reflects their origin and/or evolution. Most of the coma species visible in the optical were extensively observed in the past. The analysis of these gas coma constituents, mainly daughter products produced for the most part by photolytic destruction of their parent species, is therefore of major importance, if we want to draw conclusions on diversities and similarities of comets in terms of coma composition on a statistically relevant basis. Hundreds of gas and dust production rates are published, but have never been combined into a single database that would allow identifying whether and how the abundances of coma species differ from comet to comet and how they vary with heliocentric distance and with the number of apparitions. A common database can however only be established if the production rates are re-calculated with a common model and set of parameters.

This paper presents the scientific case for a next generation adaptive optics instrument at the VLT, temporarily named “Planet Finder”, that is aimed at detecting and characterizing extrasolar planets through the direct analysis of their emitted photons in the visible and at near-IR wavelengths. We discuss the observational niche of such an instrument to have first light in 2010, in complement to other planet search methods. To improve the efficiency (and consistency) of the search for planets with the PF, the observations will need to be organized in the form of an extensive survey of hundreds of nearby stars, predicted outputs of which are also described here. This summarizes the study phase of the instrument, conducted by two competitive teams and the recent merging of both studies, regarding the scientific impact of Planet Finder.

We present optical observations of the newly discovered accretion powered millisecond pulsar IGR J00291+5934, undertaken in the weeks following its outburst on 2$^{nd}$ December 2004. The decay to quiescence is seen to be highly variable with no indication of a modulation on the $\sim$2.46 hr orbital period apparent in the data, consistent with a system at low inclination. We also have a single Keck LRIS spectrum of the companion to IGR J00291+5934 taken 10 days after outburst. Strong hydrogen and helium emission lines are observed confirming the identity of the counterpart.

Pathways leading to the formation of complex organic molecules are described. Gas-phase processes that may build large carbon-chain species in cold molecular clouds are summarised. Catalytic reactions on grain surfaces can lead to a large variety of organic species, and model calculations of mantle formation by atom additions to multiply-bonded molecules are presented. The subsequent desorption of these mixed molecular ices can initiate a distinctive organic chemistry via ion-molecule pathways. The predictions of this theory are briefly compared with observations to show how possible organic formation pathways in the interstellar medium may be constrained.

We have examined some basic properties of damped Ly$\alpha$ systems (DLAs) by semi-analytic modelling. We assume that DLA hosts are disk galaxies whose mass function is generated by a Press-Schechter formalism at redshift 3. The disk undergoes star formation and chemical evolution. We select modelled DLAs according to their observational criterion by Monte Carlo simulation using random lines of sight and disk inclinations. The DLA ages are set to be 1 to 3 Gyr. By best-fitting the predicted metallicity distribution to the observed ones, we get the effective yield for DLAs of about $0.25Z_{\odot}$. On the basis of this constraint, we further compared our model predictions with observations at redshift 3 in the following properties: number density, gas content, HI frequency distribution, star formation rate density, and the relationship between metallicity and HI column density. We found that the predicted number density at redshift 3 agrees well with the observed value, but the gas content $\Omega_{DLA}$ is about 3 times larger than observed since our model predicts more DLA systems with higher column density. The frequency distribution at higher HI column density is quite consistent with observations while some difference exists at the lower HI end. The predicted star formation rate density contributed by DLAs is consistent with the most recent observations. In addition, we have investigated the connection between DLAs and Lyman Break galaxies (LBGs) by comparing their UV luminosity functions, which shows that DLAs host galaxies are much fainter than LBGs. However, there is a discrepancy between the model predictions and observations in the correlation between metallicity and HI column density for DLAs. Further investigations are needed into the mode of star formation in high redshift environments.

We present the observed metallicity distribution for 437 red giants in the Carina dwarf spheroidal (dSph) galaxy that was derived from FLAMES medium-resolution spectroscopy of the near-infrared Ca triplet (CaT). We find a mean [Fe/H] of −1.7, dex and a full spread in metallicities of at least one dex. Most of this width is due to the occurrence of three populations at different [Fe/H], which are likely to be related to the three star forming (SF) episodes that governed Carina's evolution and also correlate with peaks in the age-distribution. Both the lack of any correlation between stellar colour and metallicity and a comparison of the metallicities with chemical evolution models, which suggest a major role of infalling gas, contribute to the detailed understanding of Carina's evolutionary history. Moreover, we find a mild dependence of metallicity on radial location, reflected in a shift of the distribution's peak towards the metal poor end in the outer regions.

The Working Group on Extrasolar Planets (hereafter the WGESP) was created at a meeting of the IAU Executive Council in 1999 as a Working Group of IAU Division III and was renewed for three more years at the IAU General Assembly in 2003. The charge of the WGESP is to act as a focal point for international research on extrasolar planets. The membership of the WGESP has remained unchanged for the last three years.

Young stars on their way to the ZAMS evolve in significantly different ways depending on their mass. While the theoretical and observational properties of low- and intermediate-mass stars are rather well understood and/or empirically tested, the situation for massive stars ([gsim ]10–15 M$_\odot$) is, to say the least, still elusive. On theoretical grounds, the PMS evolution of these objects should be extremely short, or nonexistent at all. Observationally, despite a great deal of effort, the simple (or bold) predictions of simplified models of massive star formation/evolution have proved more difficult to be checked. After a brief review of the theoretical expectations, I will highlight some critical test on young stars of various masses.

The international Project “Lithium in magnetic CP stars” has been put into operation using telescopes of the Crimean Astrophysical Observatory (2.6-m reflector ZTSH), European Southern Observatory (1.4-m CAT, 1.52-m with FEROS), Mount Stromlo Observatory (74-inch), Nordic Optical Telescope Scientific Association (2.4-m with SOFIN), Special Astrophysical Observatory of the Russian Academy of Sciences (6-m BTA). Here we present an historical report of the different scientific results of this project since its beginning in 1996.

With the new discoveries that some dEs are rotationally supported and that dIs may show a large variety in star formation histories, the perceived relationships between these two families of galaxies are changing. There are at least three viable channels for the origin of dwarf elliptical galaxies with strong observational evidence that support their reality. I will discuss the observational evidence for each of these channels and the likely physical processes which determine each channel.

Classically, comets from the outer solar system (beyond the orbit of Neptune), are expected to be icy, and thus active near the Sun, while asteroids in the inner solar system (interior to the orbit of Jupiter) are expected to be relatively ice-deficient, and thus inert. Studies of anomalous objects, most recently 133P/Elst-Pizarro, challenge this classical picture, however, and suggest that either (1) subsurface ice can in fact be preserved over billions of years in small bodies in the inner solar system but still be close enough to the surface to be excavated by an impact by another body, or (2) non-gravitational dynamical evolution (primarily driven by asymmetrical outgassing) of icy bodies from the outer solar system can drive these cometary bodies onto thoroughly asteroid-like orbits, erasing all dynamical signs of their trans-Neptunian origins in the process. The question thus boils down to whether occasionally sublimating icy bodies on stable asteroid-like orbits in the inner solar system, particularly in the main asteroid belt, may in fact be native to the region or whether they must necessarily be recent arrivals.

Light reflected from planets is polarized. This basic property of planets provides the possibility for detecting and characterizing extra-solar planets using polarimetry. The expected polarization properties of extra-solar planets are discussed that can be inferred from polarimetry of “our” solar system planets. They show a large variety of characteristics depending on the atmospheric and/or surface properties. Best candidates for a polarimetric detection are extra-solar planets with an optically thick Rayleigh scattering layer.

Even the detection of highly polarized extra-solar planets requires a very sophisticated instrument. We present the results from a phase A (feasibility) study for a polarimetric arm in the ESO VLT planet finder instrument. It is shown that giant planets around nearby stars can be searched and investigated with an imaging polarimeter, combined with a powerful AO system and a coronagraph at an 8 m class telescope.

A similar type of polarimeter is also considered for the direct detection of terrestrial planets using an AO system on one of the future Extremely Large Telescopes.

We present semi-analytic models and Monte-Carlo simulations of QSO Ly$\alpha$ absorption line systems which originate in gaseous galactic halos, galaxy disks, and satellite halos around central galaxies. The relation between the properties of predicted absorption lines and those of galaxies has been investigated. Using a model with galactic halos, satellites, and HI disks of spirals, 60 % of the observed strong Ly$\alpha$ lines and all of the Lyman-limit systems can be predicted. The models predict $W_r \propto \rho^{-\alpha} L_B^{\beta} (1+z)^{-\gamma}$ with $\alpha \sim 0.5, \beta \sim 0.15, \gamma \sim 0.5$. For strong Ly$\alpha$ lines the average covering factor within $250 h^{-1} \kpc$ is $\sim 0.36$, with an average absorption radius of $\sim 150 h^{-1} \kpc$ for a galaxy halo, in good agreement with observations. Using mock imaging and spectroscopic surveys, selection effects are found to be able to strengthen the anti-correlation between line width and projected distance. The models were also applied to quasar metal absorption lines and more realistic absorption spectra with noise were simulated.

2-D and 3-D radiation transfer models of forming stars generally produce bluer 1-10 μm colors than 1-D models of the same evolutionary state and envelope mass. Therefore, 1-D models of the shortwave radiation will generally estimate a lower envelope mass and later evolutionary state than multidimensional models. 1-D models are probably reasonable for very young sources, or longwave analysis ($\lambda >100 \mu$m). In our 3-D models of high-mass stars in clumpy molecular clouds, we find no correlation between the depth of the 10 μm silicate feature and the longwave ($> 100 \mu$m) SED (which sets the envelope mass), even when the average optical extinction of the envelope is ${> }100$ magnitudes. This is in agreement with the observations of Faison et al. (1998) of several UltraCompact HII (UCHII) regions, suggesting that many of these sources are more evolved than embedded protostars.

We have calculated a large grid of 2-D models and find substantial overlap between different evolutionary states in the mid-IR color-color diagrams. We have developed a model fitter to work in conjunction with the grid to analyze large datasets. This grid and fitter will be expanded and tested in 2005 and released to the public in 2006.

We report on results of VLT/FLAMES observations of the very old cluster Cr 261. We compare the results with those of other clusters older than the Hyades.

The inventory of interstellar and solar system molecules now numbers well over 100 species, including both ions and neutrals. Gas-phase formation routes to many of the observed organics are still uncertain, so that solid-phase syntheses are of interest. Low-temperature reactions are thought to occur within interstellar ices, on ice and grain surfaces in the interstellar medium (ISM), and on icy surfaces of solar system objects (e.g., Europa, Pluto). Ionizing radiation, such as cosmic rays, and far-UV photons are two possible initiators of such chemistry.

In the Cosmic Ice Lab at NASA's Goddard Space Flight Center, we can study both the photo-and radiation-induced chemistries of ices at 8–300 K. Our most-recent work has been motivated by the detections of ethylene glycol, HOCH2CH2OH, in the ISM (Hollis et al. 2002) and in comet Hale-Bopp (Crovisier et al. 2002). Ethylene glycol is currently the largest firmly-identified cometary molecule as well as one of the larger interstellar organics. It's formation and accompanying chemistry provide challenges and tests for current astrochemical thought.

Here we discuss laboratory experiments on ethylene glycol's solid-phase formation and destruction. Using infrared spectroscopy, we have identified low-temperature radiation-chemical pathways that lead from known interstellar ices, such as either CH3OH or H<2O and CO, to ethylene glycol. We also have identified a role for ethylene glycol in the formation of glycolaldehyde, HOCH2C(O)H, a simple sugar (Hollis, Lovas, & Jewell 2000). Related to these results are the 6-and 7-atom molecules formed by oxidation and reduction processes in irradiated H2O + C2H<2 ices. Analogous experiments have been conducted on two other triply-bonded molecules in H<2O-rich ice, HCN and N2. An important focus of our work is the development of reaction schemes for the formation of complex molecules within astrochemically-relevant ices, and the use of such schemes to predict new molecules awaiting detection.

A key pursuit of 10-meter-class optical-infrared telescopes is to use deep imaging and spectroscopic surveys to track the evolution of galaxy structure. Future telescopes will continue this quest back to the epoch of the first galaxies, reaching ever fainter structures at ever higher redshifts. Apertures of 20, 30, 50, and 100 meters equipped with the latest in adaptive optics will look out from the world's foremost observing sites, and incrementally improve on point-source sensitivity. But how will they compare for studying extended structures? Scientific avenues that can be pursued with poorer spatial resolution, but require low backgrounds - for example, tracing the formation history of bulges - might allow for tradeoffs between aperture, site, and cost. To explore this parameter space I use a published model of average seeing at any site, develop a simple telescope performance and cost model, and simulate resultant galaxy images over a wide range of absolute brightness, size, bulge fraction, inclination, and redshift. I present a graphical interface to the model which allows side-by-side visual comparison of a given galaxy for any two observatories. This approach is intuitive and flexible, although probably not well suited for detailed analysis of a particular telescope. I compare observatory cost against the relative accuracy of measured galaxy bulge-to-total ratio, and comment on telescope and site requirements.

The WGNEO, a Working Group of Divisions I and III, was formed in the early 1990s to coordinate study of Earth-approaching asteroids and comets (NEOs) and provide timely advice to the General Secretary and officers of the IAU on discovery of any objects that threaten collision with the Earth. Since then, the WGNEO has steadily grown, reflecting increasing international interest and concern over impacts, especially from asteroids (which dominate over comets in their risk to Earth). In this triennium, the WGNEO had a membership of 49 (including the Organizing Committee of 17 members), plus 10 consultants. The Chair is David Morrison (USA), Vice-Chair Andrea Milani (Italy), Secretary Richard Binzel (USA), and Past-Chair Andrea Carusi (Italy).

The Gamma-ray Large Area Space Telescope (GLAST) is an international and multi-agency space mission that will study the cosmos in the energy range 10 keV – 300 GeV. The GLAST Science Support Center (GSSC) is the scientific community's interface with GLAST. The GSSC will provide data, analysis software and documentation. In addition, the GSSC will administer the guest investigator program for NASA HQ. Consequently, the GSSC will provide proposal preparation tools to assist proposers in assessing the feasibility of observing sources of interest.