The physical state of the intergalactic medium can be probed in great detail with the intervening absorption systems seen in quasar spectra. The properties of the hydrogen absorbers depend on many cosmological parameters, such as the matter power spectrum, reionisation history, ionising background and the nature of the dark matter. The spectra also contain metal lines, which can be used to constrain the star formation history and the feedback processes acting in large and small galaxies. Simulations have been instrumental in investigating to what extent these parameters can be unambiguously constrained with current and future data. This paper is meant as an introduction to this subject, and reviews techniques and methods for simulating the intergalactic medium.

Diffuse clouds are defined as low-density clouds permeated by the ultraviolet interstellar radiation field. We discuss the ensemble of atomic, ionic and molecular observations in the context of our Photon Dominated Region model. The comparison with all observational constraints is limited and implies that the diffuse environment is more complex than originally thought.

The growing number of observational details questions the standard picture of the evolution of dwarf ellipticals and argues for a complex evolution dominateded by environmental effects. Here we compile some standard and most recent observational issues and discuss the results of simple models in comparison with observations. The necessity of further model developments are justified and prospected.

The AMS-02 experiment is a large acceptance magnetic spectrometer which will operate on the International Space Station for more than 3 years. This will allow to perform high statistics studies of cosmic rays in space and the accurate determination of secondary-to-primary ratios such as B/C, and the ratio $^{10}$Be/$^{9}$B, thus allowing to discriminate among the possible propagation models and to infer other clues about the light elements production.

Dynamical studies of the centers of galaxies have received a tremendous push forward with the launch of the Hubble Space Telescope. Thanks to its superb resolution power, HST has made it possible not only to convincingly demonstrate the existence of supermassive black holes (SBHs) in galactic nuclei, but also to investigate how SBHs relate to the overall structure of the host galaxy. In spite of this, many questions remain unanswered, for instance, how do scaling relations for SBHs evolve with cosmic time? What is the exact characterization of the local SBH mass function? Are there upper and lower limits to the mass a SBH can attain? The next generation of 30m telescopes will provide the leap in resolution capabilities and collective power which is necessary to address the above questions. I will discuss some of the main science drivers in the field of galaxy dynamics, and the instrument requirements needed to achieve them.

The paper focuses on the issues for detection of life by remote observations. The problem is divided into the detection of terrestrial planets and the detection of life on them. The problem of detection of planets is compared with the observations of the Hubble Deep Field. The difficulty of detection will likely result in many interesting discoveries before detection techniques are adequate. It is proposed that life is the activity of mutually assisting persistence processes. A persistence process is one that uses the Gibbs Free Energy of the environment for repair and development. It is pointed out that because life produces approximations to equilibrium it is intrinsically difficult to detect by remote observations. Chemical signs of life will be distinctive if the abiotic processes that might produce them are implausible, and preferably absent. The ease of remote detection of terrestrial life is contrasted with problems likely to arise for other planets. It is recommended that initial searches be focused on giant planets. The spectral region of the discovery observations will be set by technical issues which are not yet resolved for any technique. For determining whether life is present, as many spectral regions as possible should be observed.

Methanol masers which are traditionally divided into two classes provide possibility to study important parts of the star forming regions: Class II masers trace vicinities of the massive YSOs while class I masers are likely to trace more distant parts of the outflows where newer stars can form.

There are many methanol transitions which produce observed masers. This allows to use pumping analysis for estimation of the physical parameters in the maser formation regions and its environment, for the study of their evolution. Extensive surveys in different masing transitions allow to conclude on the values of the temperatures, densities, dust properties, etc. in the bulk of masing regions. Variability of the brightest masers is monitored during several years. In some cases it is probably caused by the changes of the dust temperature which follow variations in the brightness of the central YSO reflecting the character of the accretion process.

A unified catalogue of the class II methanol masers consisting of more than 500 objects is compiled. Analysis of the data shows that: physical conditions within the usual maser source vary considerably; maser brightness is determined by parameters of some distinguished part of the object–maser formation region; class II methanol masers are formed not within the outflows but in the regions affected by their propagation.

It is shown that the “near” solutions for the kinematic distances to the sources can be used for statistical analysis. The luminosity function of the 6.7 GHz methanol masers is constructed. It is shown that improvement of the sensitivity of surveys can increase number of detected maser sources considerably.

The distribution of class II methanol masers in the Galaxy is constructed on the basis of estimated kinematic distances. It is shown that most of the sources are located in the Molecular Ring and that the dependence of the number of sources on the distance from the Galactic Center has significant peaks at the positions corresponding to the spiral arms.

A survey of CS(2-1) line emission tracing dense gas is performed at Mopra toward the positions of the brightest class II methanol masers. Velocity correlations between the maser and CS lines are analyzed. It is shown that the sources with l from 320 to 350 deg in which the masers are relatively blue-shifted, form a group which is located in the region of the Scutum-Centaurus spiral arm. This can reflect existence of a grand design, i.e., grouping of the sources with similar peculiarity of morphology or evolutionary stage of the massive star forming regions.

We present selected results of observations and monitoring of cataclysmic variables (CVs) and related objects by the instruments IBIS and OMC onboard INTEGRAL. We analyse the behaviour of the intermediate polar (IP) V1223 Sgr in a state which we call a shallow low state. We present far X-ray spectra ($E$ up to 60 keV), and the optical and far X-ray orbital modulation. The relation between far X-ray and optical flux appears to be stable over about 400 days. We also present far X-ray observations of some other CVs (or at least upper limits of their far X-ray fluxes) and show that the systems with magnetized white dwarf (like polars and IPs) are observable with INTEGRAL. The OMC light curves show that an outburst and a shallow low state of IX Vel are caused by the mass transfer variations, and not by the thermal instability of the disk, and that the amplitude of the flickering decreases with the decreasing intensity of the “stable” component.

Historically, there have been two main groups dealing with the investigation of extraterrestrial life and habitable worlds. The first is IAU Commission 51, composed of astronomers, physicists and engineers who focus on the search for extrasolar planets, formation and evolution of planetary systems, and the astronomical search for intelligent signals. The second group, the International Society for the Study of the Origin of Life (ISSOL), is composed largely of biologists and chemists focusing research on the biogenesis and evolution of life on Earth and in the solar system. There are now a variety of international organizations dedicated to this field, and this triennium has seen the beginnings of coordination and interaction between the groups through the Federation of Astrobiology Organizations, FAO.

Non-gravitational perturbations, regardless being many orders of magnitude weaker than gravity, hold keys to fully understand the evolution of small Solar System bodies. This is because individual bodies, or their entire groups, manifest traces of a long-term accumulated changes by these effects.

For meteoroids and small asteroids in the 10 cm–10 km size range, the principal non-gravitational force and torque arise from an anisotropic thermal emission of the absorbed solar radiation. Related perturbations of the orbital and rotational motion are called the Yarkovsky and YORP effects.

We review the most important Yarkovsky- and YORP-driven processes, in the Main Asteroid Belt. These include: steady and size-dependent semimajor axis drift, secular changes of rotational period and obliquity, efficient transport towards low-order resonances, interaction with weaker higher-order resonances, captures in secular and spin-orbit resonances.

Many independent observations can be naturally interpreted in the framework of Yarkov-sky/YORP models, like cosmic ray exposure ages of meteorites, current population and size-distribution of near-Earth objects, the existence of unstable resonant asteroids or the structure of asteroid families.

We use recent observations of the HI mass function to constrain the amount of cold gas in dark matter halos. It is found that the cold gas mass in a halo decreases rapidly with decreasing halo mass for low-mass halos with $M<10^{12} h^{-1}{\rm M_\odot}$. This result is in conflict with the standard model, in which most of the gas in a low-mass halo is assumed to settle into a gaseous disk, and the cold gas is depleted by star formation and supernova-driven outflow until the disk becomes gravitationally stable. Heating by the UV background can reduce the amount of cold gas in halos with masses $<10^{10} h^{-1}{\rm M}_\odot$, but is insufficient to explain the observational result. A consistent model can be found if low-mass halos are embedded in a preheated medium, with a specific gas entropy $\sim 10\,{\rm keV\,cm^{2}}$. Such a model can also explain why the faint-end slope of the galaxy luminosity function is flat. We propose a preheating model in which the medium around low-mass halos is preheated by gravitational pancaking. Since large-scale tidal fields tend to suppress the formation of low-mass virialised halos while promoting the formation of pancakes, the formation of massive pancakes may precede that of low-mass dark halos at the present time. ‘Previrialisation’ of such pancakes can heat the intergalactic medium. The preheated gas has a cooling time longer than the age of the Universe at $z\lesssim 2$, and has a specific entropy comparable to that required to reduce the amount of cold gas and star formation activity in galaxy halos.

I will review the progress of VLT spectroscopy of large numbers of individual stars in nearby dwarf spheroidal galaxies. This spectroscopy has allowed us to obtain detailed insights into the chemical and dynamical properties of the resolved stellar population in these nearby systems.

Our mid-infrared and near-infrared surveys over the last five years have helped to strengthen and clarify the relationships between water, methanol, and OH masers and the star formation process. Our surveys show that maser emission seems to be more closely associated with mid-infrared emission than cm radio continuum emission from UC HII regions. We find that masers of all molecular species surveyed trace a wide variety of phenomena and show a proclivity for linear distributions. The vast majority of these linear distributions can be explained by outflows or shocks, and in general do not appear to trace circumstellar disks as was previously thought. Some water and methanol masers that are not associated with radio continuum emission appear to trace infrared-bright hot cores, the earliest observable stage of massive stellar life before the onset of a UC HII region.

The presence of large organic species in interstellar gas has important implications for the origin of life and pre-biotic chemistry. Accurate identifications of such molecules, however, are problematic in molecular clouds. There are many reasons for such difficulties. One is that the spectral density is very high in objects where the chemistry is sufficiently complex to produce such species—at least 10 lines per 100 MHz in Sgr B2(N), for example, at 3 mm, at a sensitivity of 10 mK peak-to-peak. Hence, the possibility of chance coincidences is large. Another reason is the presence of many large organic molecules at relatively high temperatures; these large asymmetric tops have vast numbers of favorable transitions under these conditions, including those originating from low-lying vibrational states. Confusion and blending of transitions of one large molecule with those of another add to the risks of an inaccurate identification.

A case in point is that of glycolaldehyde, CH$_2$OHCHO. In order to confirm the identification of this molecule in Sgr B2(N), we searched for its most favorable transitions in the 2 and 3 mm windows, spanning the energy range of ${\sim}$10–100 K—a total of 43 individual transitions. Of all these lines, only seven were not heavily blended or contaminated by other molecules, i.e. so-called “clean” features. Emission, however, was visibly detected at 34 of the other transitions, but one transition was clearly absent. The “missing” line corresponds to a weak transition originating in the $K_a =$ 3 ladder, and its absence is consistent with the other detected features. Based on the clean features only, glycolaldehyde has a $V_{LSR} = 61.7 \pm 1.5$ kms$^{-1}$ and $\Delta V_{1/2} = 7.8 \pm 1.8$ kms$^{-1}$ with intensities consistently in the range $T_R^* \sim 20-70$ mK. Given these data, the identification of glycolaldehyde is 99.9% secure. A rotational diagram from this data set yields a column density of $N_{tot} \sim 6 \times 10^{13}$ cm$^{-2}$ for CH$_2$OHCHO—roughly a factor of 27 less than that of H$_2$CO. These data illustrate the problems and subtleties in identifying large organic molecules in space.

The combination of the collecting power of an ELT with an ultra-stable high resolution spectrograph opens up the possibility to measure for the first time directly the dynamical effect of the acceleration of the Universe. CODEX will also provide unique opportunities for advance in many other branches of astrophysics. The CODEX design is based on an array of several identical spectrographs. It is highly modular and can be easily adapted to a large range of sky apertures and telescope diameters. CODEX is designed to work as a seeing limited instrument. The requirements for the telescope are moderate and clearly identified.

Effective temperatures of 30 turnoff stars with $-3.2 {<}$[Fe/H]${<}{-}1.5$ have been derived from the profiles of Balmer lines in high S/N, VLT/UVES spectra. While the systematic error of $T_{\rm eff}$ may be of the order of 100K, the differential values of $T_{\rm eff}$ are determined with a one-sigma precision of ${\sim}25$K. These precise $T_{\rm eff}$ values are used in a study of the slope and dispersion of the Li abundance as a function of [Fe/H]. A small, but significant cosmic dispersion in $A$(Li) appears to be present exemplified by the two very metal-poor stars G64-12 and G64-37.

As for comets 619 comets received names from July 2002 to June 2005. Of this naming 76 percent are SOHO comets and 11 percent include the name of the LINEAR project. A revision of the guidelines for naming comets has been completed in March 2003. The assistance of the director of CBAT, Daniel W. E. Green, in redrafting these guidelines was much appreciated by the committee.

Instruments will be briefly introduced and the main mission results to date will be described.

We present simulations which demonstrate to which extent mid-infrared images and millimeter maps can be used to trace the location of giant planets in circumstellar disks. The most promising approach is to look for characteristic signatures in circumstellar disks caused by the interaction of giant planets with the disk. Numerical simulations show that these signatures are usually in size much larger than the planet itself and thus much easier to detect. The particular result of the planet-disk-interaction depends on the evolutionary stage of the disk. Primary signatures of planets embedded in disks are gaps in the case of young disks and characteristic asymmetric density patterns in debris disks. Radiative transfer simulations predict that high spatial resolution observations performed with instruments/telescopes that will become available in the near future will allow to trace the formation and evolution of planets in protoplanetary and debris disks.

In the next generation surveys, the discovery of moving objects can be successful only if an observation strategy and the identification/orbit determination procedure are appropriate for the diverse apparent motions of the target sub-populations. The observations must accurately measure the displacement over a short interval of time; observations believed to belong to the same object have to be connected into tracklets. Information contained in tracklets is in most cases not sufficient to compute an orbit: two or more of them must be identified to provide an orbit. We have developed a method for recursive identification of tracklets allowing an unbiased orbit determination for all sub-populations and efficient enough to cope with the data flow expected from the next generation surveys. The success of the new algorithms can be easily measured only in a simulation, by consulting a posteriori some “ground truth”.

We present here the results of a simulation of the orbit determination for one month of operations of the future Pan-STARRS survey, based upon a Solar System Model with a downsized population of Main Belt asteroids and a full size populations of Trojans, NEO, Centaurs, Comets and TNO. The results indicate that the method already developed and tested to find identifications of NEO and Main Belt asteroids are directly applicable to Trojans. The more distant objects often require modified algorithms, fitting orbits with only 4 parameters in a coordinate system specially adapted to handle very short arcs of observations. These orbits are mostly used as intermediate results, allowing to find full solutions as more tracklets are identified.

When the number density of detections is as large as expected from the next generation surveys, both joining observations into tracklets and identifying tracklets can produce some false results. The only reliable way to remove them is a procedure of tracklet/identification management. It compares the tracklets and the identifications with a complex logic, allowing to discard almost all the false tracklets and all the false identifications. However, the distant objects still present a challenge for orbit determination: they require three tracklets in separate nights. If this requirement is met we have found no problem in achieving an unbiased orbit determination for all populations. Further work will lead to more advanced simulations, in particular by introducing a realistic model for astrometric and photometric errors.