The association of “long” Gamma-Ray Bursts (durations > 2 seconds) with peculiar Type Ic supernovae suggests strongly that this type of GRB is produced by the collapse of the rapidly rotating core of an initially very massive star to a black hole. At the time of collapse the star has lost its hydrogen-rich envelope and the GRB is thought to be produced by a collimated relativistic jet of matter ejected along the star's rotation axis. The angular momentum constraints for producing such a “collapsar” or “hypernova” suggest that the GRB-producing core collapses constitute only a small fraction of all core collapses of massive stars. As to the short-duration GRBs (< 2 seconds), which make up about one third of all GRBs, the most favoured model is that of the coalescence of a double neutron star or of a neutron star-black hole binary. Also these events are expected to be very rare, having a frequency of at most one event per hundred thousand years for a galaxy like our own. Due to the collimation of the relativistically ejected matter, the observable frequency of GRB events will, like in the case of the “long” bursts, be at least a factor hundred smaller.

The study of the molecular gas in quasars and submillimeter galaxies at high redshift has significantly progressed during the last few years. From the current detection of CO emission in 37 sources spanning a range in redshift from $1<z<6.4$ with, in some cases, the measurement of a series of CO rotational transitions, it is possible to constrain the physical conditions of the massive ($\ge 10^{10} \, M_\odot$) reservoirs of gas in these objects. This review will present the current status of the studies of molecular gas in high-$z$ sources, detail the physical conditions which pertain in these systems, which are scaled-up versions of the local ULIRGS, and discuss the searches in high-$z$ sources for species other than CO, including the fine structure lines of neutral carbon and the recent detection of the redshifted [CII] emission line in the $z=6.4$ quasar J 1148+5251. These results hold great promise for the study of galaxy formation and their evolution with redshift. This review will conclude by outlining the expected progress in the field, in particular when future instruments such as ALMA will be operational, which will enable to study the astrochemistry and its evolution in the early universe.

The massive star clusters identified by S. Larsen are compared to the available Chandra observations of face-on spiral galaxies. In each galaxy, a few percent of the Larsen-identified clusters match X-ray-emitting point sources. An additional few match knots of emission in the diffuse emission. The cluster properties are examined to ascertain whether massive star clusters are X-ray sources.

We have discovered a number of nonthermal X-ray features within central 40 pc region of the Galactic center by analysing 600-ksec observations of Chandra archival data. Most of the detected X-ray structures exhibit small-scale knot-like morphologies and their spectra are well reproduced by single hard power-law with photon indices of 1-2. Among them, the most outstanding features are the three X-ray knots which are aligned on a straight line from the potition of Sgr A* to north-northwest direction. The X-ray properties of these knots lead us to suspect that they are X-ray jets ejected from Sgr A* in the recent past. In addition, we have obtained an indication that the summed flux of nonthermal diffuse X-rays within 30 pc of the GC seems to be smoothly connected to the 20-100 keV flux detected with INTEGRAL IBIS/ISGRI. These results suggest that the origin of GC hard X-rays (or High energy Gamma-rays) is not (or partly) from the Galactic nucleus.

The Very Energy Radiation Imaging Telescope Array System (VERITAS) in its first phase of operation will consist of an array of 4 Imaging Atmospheric Cherenkov Telescopes (IACTs) arranged in a ‘Mercedes’ star configuration. To be located at a high, dark site in Southern Arizona the full array is expected to see first light in October 2006. In February of 2005 the first VERITAS telescope achieved first light at a temporary location near to the final site. This poster summarises the status of the VERITAS instruments as of summer 2005.

A series of experiments on the surface reactions of hydrogen and deuterium atoms with solid CO, formaldehyde (H2CO), and methanol (CH3OH) has been performed. Successive hydrogenation of CO on surfaces at $\sim $10 K was found to proceed efficiently via tunneling to produce H2CO and CH3OH on dust grains under the typical conditions of molecular clouds. Formation rates are strongly dependent on the surface temperature and composition. The role of surface reactions in the formation of deuterated formaldehyde and methanol was investigated. The deuterium fractionation of methanol observed in molecular clouds was reproduced experimentally via H-D substitution in solid methanol at an accreting atomic D/H ratio of 0.05-0.1. This is the first evidence that grain-surface reactions can be responsible for fractionation. We have determined several effective rate constants for hydrogenation, deuteration, and H-D substitution to construct the surface reaction network for CO, H2CO, CH3OH, deuterated formaldehyde, and deuterated methanol.

Since its launch in October 2002, the INTEGRAL satellite has observed the X-ray binary and black hole (BH) candidate GRS 1758–258, for more than 2 Ms. Between 2003 and 2004 INTEGRAL could follow its spectral and temporal behaviour: while it was weak and soft in spring 2003 it was detected up to 150 keV at the end of 2003 August, in a hard state similar to the one observed between 1990 and 1997 by previous high energy missions.

Population synthesis of binary stars with relativistic component is presented.

Recent observations in visible photometry have provided B, V, R and I high quality colors for more than 130 objects. Color diversity is now a reality in the TNOs population. Relevant statistical analyses have been performed and all possible correlations between optical colors and orbital parameters have been analyzed. A taxonomy scheme based on multivariate statistical analysis of a subsample of 51 objects described by the 4 color indices (B-V, V-R, V-I and V-J) has been obtained. A tentative interpretation of the obtained groups in terms of surface characteristics is given. Moreover, an extension of this taxonomy to the other 84 objects for which only three colors indices (B-V, V-R, and V-I) are available, is also presented.

The faintness of these objects limits the spectroscopic observations. Despite this, our group provided visible and infrared spectra for 18 objects using the Very Large Telescope (ESO, Paranal, Chile). The wavelength region ranging 0.4–2.3 microns encompasses diagnostic spectral features to investigate organic compounds, minerals and ices present on the surface of the TNOs. The investigation of the surface variation can be an identifier of possible composition diversity and/or different evolution with different physical processes affecting the surface.

The current knowledge of the surface properties and composition of the population will be presented, analyzed and interpreted.

This paper will review the main astrophysical results obtained in the field of high energy Galactic sources with the INTEGRAL/IBIS Gamma-ray Imager (Ubertini et al. 2003) on-board INTEGRAL (Winkler et al. 2003), the ESA space Observatory successfully launched the 17th October 2002 from Baikonur with a Proton vehicle. In view of the high sensitivity of the two gamma ray instruments IBIS and SPI and their capability to provide at the same time image, spectra and time profiles of all the sources in their wide field of view, a key project was approved as “Core Programme” to deeply observe the Galactic Centre (GCDE) and to exploit regular scans of the whole Galaxy Plane. The major results obtained in terms of classes of high energy emitters are shortly outlined.

Dawn is the first mission to attempt to orbit two distant planetary bodies. The objects chosen, 4 Vesta followed by 1 Ceres, are the two most massive members of the asteroid belt that appear to have been formed on either side of the dew line in the early solar nebula. This paper describes the present status of the mission development and the plans for operation at Vesta and Ceres.

A substantial number of stars was detected in the ROSAT All Sky Survey. Analysis of these data indicates a systematic shift in the distribution of their X-ray hardness ratios, from late type dwarfs to late type giants to early type stars, that can be attributed to systematic differences in line-of-sight absorption.

High energy gamma-ray astronomy has recently made significant progresss through ground-based instruments like the H.E.S.S. array of imaging atmospheric Cherenkov telescopes. The unprecedented angular resolution and the large field of view has allowed to spatially resolve for the first time the morphology of gamma-ray sources in the TeV energy range. The experimental technique is described and the types of sources detected and still expected are discussed. Selected results include objects as different as a Galactic binary Pulsar, the Galactic Center and Supernova Remnants but they also concern the diffuse extragalactic optical/infrared radiation field. Finally, a scan of the Galactic plane in TeV gamma rays is described which has led to a significant number of new TeV sources, many of which are still unidentified in other wavelengths. The field has a close connection with X-ray astronomy which allows the study of the synchrotron emission from these very high energy sources.

Using 24 overlapping XMM-Newton observations of the Local Group spiral galaxy M 33, we have detected 447 sources in each individual pointing and in deep combined images. A total of 61 sources exhibit significant flux variations by a factor of up to 144, on time scales of hours to months or years. The detected variability, together with the hardness ratio (HR) method and optical identification (when available), is used to classify the sources as X-ray binaries (XRBs), supernova remnants (SNRs) and super-soft sources (SSS) in M 33, as well as background AGN and foreground stars in the field of view. The majority of sources can only be classified as ‘hard’, according to their HRs. We find that the luminosity distribution of the detected SNRs and SNR candidates in M 33 is similar to M 31, and slightly steeper than that of the LMC.

We present the results of population synthesis simulations aimed at exploring the evolution of the 2–10 keV luminosity of X-ray binaries in a young stellar population. The results are applicable to populations of extragalactic X-ray binaries in starburst galaxies and many LINERs. We find that the integrated 2–10 keV luminosity of the simulated population reaches a maximum of about $10^{40}\,{\rm erg~s}^{-1}$ after approximately 20 Myr (for a star-formation rate of 10 M$_{\odot}$ yr$^{-1}$) and remains significant even after the end of star formation and the demise of the luminous OB stars. The results of our simulation are in agreement with recently-derived correlations between the X-ray luminosity starburst galaxies and their star-formation rate. We also find that the cumulative luminosity function is initially fairly flat, in agreement with recent observational results, becoming steeper as the population ages and the high-mass X-ray binaries are succeeded by binaries with progressively lighter donor stars. Using the output of Hydrogen-ionizing far-UV photons from the stellar population, we can plot the track of a “post-starburst” system in the $L_{\rm X}-L_{\rm H\alpha}$ diagram. The system starts off in the starburst locus but quickly evolves to the AGN locus where it lingers for at least 1 Gyr.

We review the main laboratory results of investigations of processes of molecular hydrogen formation on surfaces. The problem of the formation of molecular hydrogen is a fundamental issue in astrophysics/astrochemistry, because of the great importance that molecular hydrogen has for the structure and evolution of our Universe. Such experiments are done using ultra-high vacuum, low temperature, and atomic/molecular beam techniques to study the formation of molecular hydrogen on dust grain analogues in conditions as close as technically feasible to the ones present in relevant ISM environments. In experiments conducted at Syracuse University, we studied H2 formation on the three most ISM-relevant classes of surfaces: silicates, carbonaceous materials and amorphous water ice. Our experimental investigations range from the evaluation of the catalytic efficiency of the studied surfaces to the energetics of the reaction, i.e. the partition of the formation energy between the grain and the nascent molecule. Such measurements have been done by changing various parameters such as: the temperature of the interstellar dust analogue, the kinetic temperature of the atoms, the morphology of the surface and, to be completed soon, the composition of the solid. Quantitative and qualitative information on the processes of H2 formation is then fed in theoretical models to extract results that pertain to desired ISM environments.

A mid-infrared high-resolution spectral survey of the source IRC+10216 (CW Leo) has been carried out between 11 and 14 $\mu$m. A large number of lines of C$_2$H$_2$ and HCN and their most abundant isotopologues, have been identified. Lines involving high-energy ro-vibrational levels allow an accurate derivation of the physical and chemical conditions in the innermost envelope. We have developed a radiative transfer model capable of fitting the observed lines satisfactorily. The fit of more than 200 ro-vibrational lines allowed us to get the kinetic, vibrational and rotational temperatures and the abundances of the C$_2$H$_2$ and HCN between 1 and 300 R$_*$.

Based on over two decades of experimental, observational, and theoretical studies by scientists around the world, it is now widely accepted that the composite emission of mixtures of vibrationally-excited PAHs and PAH ions can accommodate the general pattern of band positions, intensities, and profiles observed in the discrete IR emission features of carbon-rich interstellar dust, as well as the variations in those characteristics. These variations provide insight into the detailed nature of the emitting PAH population and reflect conditions within the emitting regions giving this population enormous potential as probes of astrophysical environments. Moreover, the ubiquity and abundance of this material has impacts that extend well beyond the IR.

In this paper we will examine recent, combined experimental, theoretical, and observational studies that indicate that nitrogen-substituted PAHs represent an important component of the interstellar dust population, and we will go on to explore some of the ramifications of this result. We will also explore the results of recent experimental studies of the strong, low-lying electronic transitions of ionized PAH ions in the near-IR (0.7–2.5 $\mu$m) and explore the role that these transitions might play in pumping the PAH IR emission in regions of low excitation.

Chandra and XMM-Newton improve our understanding of X-ray populations in galaxies. In particular, there exists a class of ultra-luminous X-ray sources (ULXs) for which the observed luminosity is greater than $10^{39}$ ergs s$^{-1}$. ULXs are of great interest since they represent a population of possible intermediate-mass black holes. While the spectra of majority of ULXs are similar to Galactic X-ray binaries, a few ULXs have very soft X-ray emission ($kT=50$–100 eV) resembling supersoft X-ray sources (SSSs) discovered in the Milky Way and the Magellanic Clouds. We here report some recent multiwavelength observations of three ultra-luminous SSSs in M101, NGC 300, and the Antennae. They have shown many interesting behaviors such as state transitions, spectral changes, and time variabilities in different timescales. Unlike typical SSSs, ultra-luminous SSSs are unlikely associated with white dwarfs because of the high X-ray luminosities. We discuss some binary models involving stellar-mass and intermediate-mass black holes to explain the nature of the systems.

We report the results from an homogeneous analysis of the X-ray (ACIS-S/Chandra) data available for a sample of 52 LINER galaxies. The X-ray morphology has been classified attending to their nuclear compactness in the hard band (4.5–8.0 keV), into 2 categories: AGN-like nuclei (with a clearly identified unresolved nuclear source) and Starburst-like nuclei (without a clear nuclear source). 60% of the total sample are classified as AGNs, with a median luminosity of $\rm{L_{X}(2.0\hbox{-}10.0 keV)=2.5\times 10^{40} erg s^{-1}}$, which is an order of magnitude higher than that for SB-like nuclei. The spectral fitting allows to conclude that most of the objects need a non-negligible thermal contribution. When no spectral fitting can be performed (low signal-to-noise ratio), the Color-Color diagrams allow us to compute physical parameters such as density column, temperature of the thermal model or spectral index and therefore to analyze the origin of the X-ray emission. All X-ray morphology, spectral fitting and Color-Color diagrams allow conclude that a high percentage of LINER galaxies host AGN nuclei.