We summarise our detections of the 2175 Å feature due to dust extinction in intervening galaxies toward quasars with redshifts $z>0.9$ from the Sloan Digital Sky Survey first and second data release. For the 15 Mg II absorption systems selected from $\sim$22,000 quasar spectra, the observed extinction 2175 Å “bump” with various strengths can be well fitted using template quasar spectra reddened with dust located in the Mg II absorber redshift. The dust extinctions are characterised by either a parameterised Galactic extinction law, or empirical extinction curves for the Large Magellanic Cloud and the Small Magellanic Cloud. We observe that our sample of intervening galaxies exhibiting dust features are all strong Mg II absorbers ($EW_{\lambda 2796}>1.7$Å). The various strengths of the absorption features imply a diversity of dust properties at high redshift. The Mg II systems showing the 2175 Å absorption are characterised by their large Mg II EW, high H I column density, and heavy reddening.

I review some important questions in the field of massive star formation: What are the initial conditions for proto star clusters and how do they arise? What are the initial conditions for individual massive star formation within star clusters? How do massive protostars accumulate their mass? I compare the Turbulent Core Model (McKee & Tan 2003) to several nearby regions, including Orion KL. Here I also discuss the origin of BN's high proper motion.

Modelling and simulation, based on observational data, were used to examine the potential of ELT photometry for studies of the evolution of distant galaxies. An open cluster, a globular cluster and two mixed field populations were employed. Colour-magnitude and metallicity diagrams were examined. For younger populations, excellent turn-off-point age data and abundance data can be obtained even beyond 20Mpc. Higher population age weakens data if not improved with longer exposures. Still, the great potential of ELT photometry for studies of the evolution of galaxies is confirmed. Comments are given on adaptive optics and photometry.

First, the X-ray source populations of M31 and M33 as known from Einstein and ROSAT observations are presented. Then, chandra results on the galaxies are shortly summarized which not only spatially resolved the centre areas but also supernova remnants (SNRs) in both galaxies, and led to source catalogues of restricted areas with high astrometric accuracy. Also luminosity function studies and studies of individual sources based on chandra and XMM-Newton observations led to a better knowledge of the X-ray source populations. After that I will concentrate on XMM-Newton surveys, in which more than 850 and 400 X-ray sources were detected in M31 and M33, respectively, down to a 0.2–4.5 keV luminosity of less than 1035 erg s−1. EPIC hardness ratios as well as informations from earlier X-ray, optical, and radio catalogues were used to distinguish between different source classes (SNRs, supersoft sources (SSSs), X-ray binaries (XRBs), globular cluster sources within the galaxies, and foreground stars, and objects in the background). However, many sources could only be classified as hard.They may either be XRBs or Crab-like SNRs in the galaxies or background sources. Within M31, two globular cluster sources could be identified as low mass XRBs as they showed type I X-ray bursts. Many of the SSSs in both galaxies were identified as optical novae. Due to the high frequency of outbursts in the bulge area of M31 many novae can be monitored at the same time which makes the investigation of class properties much easier compared to novae in the Milky Way or the Magellanic Clouds.

We discuss the role of environmental mechanisms in the evolution of dwarf galaxy satellites using high-resolution N-Body+SPH simulations that include simultaneously tidal forces, ram pressure and heating from ionizing radiation fields. Tidally induced bar-buckling instabilities can transform a rotating disky dwarf into pressure supported spheroidals. Efficient gas removal requires instead a combination of tidal mass loss and ram pressure stripping in a diffuse gaseous corona around the primary system. The efficiency of ram pressure depends strongly on how extended the gas remains during the evolution. Bar driven inflows that tend to drive the gas to the bottom of the potential well can be opposed by the heating from external radiation fields. We show that even fairly massive dwarfs ($V_{peak} >$ 30 km/s) would be stripped of their gas over a few Gyr if they enter the Milky Way halo at $z > 2$ thanks to the effect of the cosmic UV background. Gas mass loss can be much faster, occurring in less than 1 Gyr, if dwarf satellites have their first close approach to the primary at the epoch of bulge formation. Indeed at that time the primary galaxy should have a FUV luminosity comparable to that of major present-day starbursts, resulting in a local UV field even more intense than the cosmic background.

The role of high spectral and spatial resolution spectroscopy in understanding the evolution of the gaseous component of circumstellar accretion disks is described. Millimeter-wave emission lines from trace constituents such as CO, CN, HCO+, and HCN can be used to probe the kinematic and physico-chemical properties in the near-surface regions of disks beyond 50–100 AU, but, thanks to extensive depletion in the midplane, they are not a reliable proxy for the disk mass. For the special case of nearly edge-on circumstellar disks, the resulting ices can be directly observed through mid-infrared spectroscopy, using ground based facilities or spacecraft (cf. Najita, this volume). Emerging and planned millimeter-wave → THz arrays will possess sufficient sensitivity and resolution to probe much closer to the central star and to search for prebiotic compounds such as those detected in comets, meteorites and interplanetary dust particles.

The search for extraterrestrial technology effectively began 45 years ago with Frank Drake's Project Ozma and a radioastronomy start to the search for extraterrestrial intelligence (SETI). Eventually searches began for possible interstellar probes in stable orbits in the Solar System, as well as for infrared excesses from possible Dyson spheres round Sun-like stars. Whilst the Cold War was still underway, some scientists looked for evidence of nuclear waste dumps and nuclear wars elsewhere in the Milky Way. None of this work was carried out by archaeologists, even though by their very nature archaeologists are experts in the detection of ancient technologies. The technologies being searched for would have been partly ancient in age though advanced in techniques and science. The development of ESA's Darwin and NASA's TPF for detection and imaging of Earth-like exoplanets in our galactic neighbourhood represents an opportunity for the testing of techniques for detecting signatures of technological activities. Ideally, both Darwin and TPF might be able to provide spectroscopic data on the chemistry and biochemistry of the atmospheres of Earth-like exoplanets, and thus to detect some of the signs of life. If this can be accomplished successfully, then in theory evidence for pollution and nuclear accidents and wars should be detectable. Some infrared signatures of ETT on or round exoplanets might be detectable. Direct visual imaging of ETT structures will probably not be feasible till we have extremely powerful interstellar telescopes or actually send orbital craft.

The triennial report from Commission 42 covers various topics like massive binaries, contact systems, cataclysmic variables and low-mass binary stars. We try in a number of sections to provide an update on the current status of the main research areas in the field of close binaries. It is not a formal review, even complete or comprehensive, but an attempt to bring the main topics on recent research to astronomers working in other fields. References are also not comprehensive and simply added to the text to help the reader looking for deeper information on the subject. For this reason, we have chosen to include references (sometimes incomplete for ongoing work) not in a list at the end but integrated with the main text body. Complete references and additional sources can be easily obtained through web access of ADS or SIMBAD. Furthermore, the summary of papers on close-binary research contained in the Bibliography of Close Binaries (BCB) can be accessed from the web site of Commission 42. I would like to express the gratitude of the commission for the careful work of Colin Scarfe as Editor-in-Chief of BCB and Andras Holl and Attila Sragli for maintaining the web pages of the Commission within the structure of Division V. Finally, K. Olah and J. Jurcsik are gratefully acknowledged for their continued support as editors of the Information Bulletin on Variable Stars (IBVS), also accessible through the commission web page.

The galaxy-IGM part of the Lyman-break survey currently consists of measured redshifts for more than 1000 galaxies with redshift $1.5\lesssim z\lesssim 3.5$ along the sight-lines to 25 background QSOs. One of the goals of the survey was to measure the influence on the intergalactic medium of energetic feedback from star and black-hole formation. This talk begins with a description of the observed correlations between galaxies and intergalactic absorption lines and ends with a discussion of whether any of the observations provide clear evidence for Mpc-scale superwinds. Although our own observations remain fairly ambiguous, other observations strongly disfavour a very high redshift ($z\sim 10$) for the creation of intergalactic metals.

A key science driver for future ELTs is to chronicle the complete formation and evolutionary histories of a meaningful number of nearby galaxies through their resolved stars. The goal will be to measure the entire star formation and chemical enrichment histories of a sample of galaxies that includes all Hubble types and covers all of their components, demanding photometry of stars in regions with high surface brightness at distances of up to 20Mpc. We present simulations that compare the abilities of 20, 30, 50, and 100m telescopes to recover the correct stellar population mix represented in field star color-magnitude diagrams observed with $J$, $H$, and $K$ filters. As input, our simulations use scenes containing stars drawn from a mix of model isochrones with differing ages and metallicities, with surface densities set to match that found in the M31 bulge and at the effective radius of NGC 3379. We convolve these scenes with PSFs corresponding to the projected performance of MCAO systems containing two deformable mirrors, including the effect of realistic variations in the atmospheric turbulence profile over the span of the observations. These simulations provide a way to evaluate the scientific advances enabled by ELTs of differing apertures in the area of extragalactic stellar populations.

Nulling interferometry is one of the promising techniques for the study of extra terrestrial planets. This technique will be applied in the future space missions Darwin and TPF-I, and from the ground with GENIE. The nulling interferometry techniques require high symmetry of the interfering beams, to obtain the required contrast (typically $10^6$ to detect terrestrial exo-planets in the thermal infrared). In this paper we consider the polarization symmetry issue, such as polarization rotation and polarization phase shifts occurring on slightly misaligned optics. We study the consequences of these symmetry requirements on a nulling interferometer design. We find the relation between the misalignment tolerances and the achievable nulling, and we show that this tolerance is highly dependent on the interferometer configuration (the way beams turn right, left, up or down in the interferometer arms). It is typically of the order of the arcminute (not the arcsecond) for a $10^6$ contrast. We present a analytical and numerical analyses.

We present preliminary results on the chemical abundance patterns of extremely metal-poor stars obtained during an ongoing observing program with Subaru/HDS. High-resolution, high signal-to-noise spectra have been obtained for 14 stars with [Fe/H]$\lesssim -3$. Five of them exhibit clear overabundances of carbon, a remarkable characteristic found only in the most metal-poor range. One of the carbon-rich stars, HE 1327–2326, has [Fe/H]$_{\rm NLTE}=-5.4$, the lowest Fe abundance known. No stars with ${-}5\,{<}\,$[Fe/H]$\,{<}\,{-}4$ have yet been found in our program, suggesting that quite different enrichment processes were responsible for stars with [Fe/H]$\,{<}\,{-}5$ and [Fe/H]$\,{>}\,{-}4$. While neutron-capture elements are deficient in most of our stars, one star (BS 16550–087) exhibits large enhancements of its light neutron-capture elements (Sr, Y and Zr), providing a strong constraint on models for the production of such elements in the very early Galaxy.

The Magellanic Clouds, consisting of the LMC, the SMC and the Bridge offer an ideal laboratory for studying cluster formation in a lower metal abundance environment at an unrivaled closeness to us among external galaxies. It is known that very young populous clusters like R136 are still being formed in the LMC, where populous clusters include more than 10000 stars tightly gravitationally bound. In this talk, I will present mm and sub-mm CO observations of the Magellanic molecular clouds obtained with NANTEN, SEST, and ASTE at spatial resolutions of 5–50pc. I will then use these CO data to identify the parent cloud cores for populous clusters and discuss the cluster formation by comparing the cloud properties with those of the Milky Way.

From October 1999 to the present Chandra has taken nearly monthly snap-shot observations of M31. The first 3 years of this dataset in combination with deeper but less frequent XMM observations has allowed the detection of 45 X-ray transients within M31. By analogy to our Galaxy, many of these transients are likely black hole candidates. We have indentified a few optical counterparts of these possible black holes via simultaneous HST imaging. The census allows a study of the endpoints of stellar evolution in our nearest neighbor galaxy. When stacked, the observations also allow a deep study of the M31 X-ray source population, which turns up a few surprises. The supermassive black hole in the center of M31 is the next nearest one after Sgr A*. Chandra and HST observations allow the detection of a weak X-ray source at the position of this SMBH. These observations provide some of the most secure and severe limitations on accretion in SMBH.

I discuss here the main physical constraints on Dark Matter particles that can be obtained by the study of the astrophysical signals produced by their annihilation within Dwarf Galaxies. The present results are obtained in the framework of neutralino Dark Matter scenarios and under the assumption that Dwarf Galaxies are dominated by Dark Matter.

Commission 34 covers diffuse matter in space on scales ranging from the circumstellar to the galactic and intergalactic. As such it has enormous scope and because of this, it alone forms Division VI. Key aspects include star formation, matter around evolved stars, astrochemistry, nebulae, galactic and intergalactic clouds and the multitude of effects of the interaction of stars with their surroundings. Associated with these areas are a huge range of physical and chemical processes including hydrodynamics and magnetohydrodynamics, radiative processes, molecular physics and chemistry, plasma processes and others too numerous to name. These are complemented by an equally huge range of observational studies using practically all space and ground-based instrumentation at nearly all observable wavelengths. A glance at any data-base of publications over the past few years attests to the vigorous state of these studies. The current membership of the Division is around 800. It also has three separate working groups.

The structure and chemistry of protoplanetary disks depends strongly on the nature of the central star around which it has formed. The dust temperature is mainly set by the stellar luminosity, while the chemistry of the upper disk layers depends on the amount of intercepted UV and X-ray flux. We discuss here the differences in chemistry, thermal structure and line emission around Herbig Ae/Be, T Tauri stars and low-mass M dwarfs. Predictions will be made for future observations with SOFIA and Herschel.

Thanks to the Sloan Digital Sky Survey, we now know that the Universe becomes opaque to Ly$\alpha$ photons at $z \sim 6$. This presents an obvious challenge for attempts to study the Universe at high redshifts with quasar absorption lines. I discuss two ways to extract more information about reionisation than the simple presence of complete Gunn-Peterson absorption. First, we still expect to see metal line absorption red-ward of Ly$\alpha$. This will allow us to probe the early phases of metal enrichment in the intergalactic medium; the lines can be quite strong because the enriched regions are relatively compact. This is particularly important because metals are a crucial feedback mechanism in the early Universe. Second, we expect to see isolated Ly$\alpha$ transmission features even before the final stages of reionisation. These features allow us to learn about the topology of reionisation and the condensation of the cosmic web at $z \sim 6$.

Stars form by gravoturbulent fragmentation of interstellar gas clouds. The supersonic turbulence ubiquitously observed in Galactic molecular gas generates strong density fluctuations with gravity taking over in the densest and most massive regions. Collapse sets in to build up stars and star clusters.

Turbulence plays a dual role. On global scales it provides support, while at the same time it can promote local collapse. Stellar birth is thus intimately linked to the dynamic behavior of parental gas clouds, which governs when and where protostellar cores form, and how they contract and grow in mass via accretion from the surrounding cloud material to build up stars. The equation of state plays a pivotal role in the fragmentation process. Under typical cloud conditions, massive stars form as part of dense clusters following the “normal” mass function observed, e.g. in the solar neighborhood. However, for gas with an effective polytropic index greater than unity star formation becomes biased towards isolated massive stars. This is relevant for understanding the properties of zero-metallicity stars (Population III) or stars that form under extreme environmental conditions like in the Galactic center or in luminous starbursts.

Disks surrounding young stars play a fundamental role in the formation of stars and planets. Accretion through disks is believed to be responsible for the build up of stellar masses, and the gas and dust in disks is a reservoir for the potential formation of planets. As a result, one of the motivations for observing the inner regions of disks (i.e., the region within 10 AU) is to obtain clues to the processes that govern how stars and planets form. Significant progress has been made over the last decade in probing the inner regions of gaseous disks through the use of infrared molecular transitions. I discuss the observational tools that are currently available to study the gaseous component. These tools can be used to explore the evolution of gas in the inner disk and thereby help us to understand the processes of giant and terrestrial planet formation. These same tools may also be used to place constraints on the physical mechanisms that drive the disk accretion process.