Related papers: Probing the interstellar medium toward GRB 221009A…
We present the most extensive and complete study of the properties for the largest sample (46 objects) of gamma-ray burst (GRB) host galaxies. The redshift interval and the mean redshift of the sample are 0<z<6.3 and z=0.96 (look-back time:…
We consider the absorption and scattering of X-rays observed from the Galactic center. One objective is to characterize the intrinsic X-ray emission from the central black hole, SgrA*, in its quiescent and flaring states. We correct the…
Dust destruction by supernovae is one of the main processes removing dust from the interstellar medium (ISM). Estimates of the efficiency of this process, both theoretical and observational, typically assume a shock propagating into a…
We analyze high resolution spectroscopic observations of the optical afterglow of GRB050730, obtained with UVES@VLT about hours after the GRB trigger. The spectrum shows that the ISM of the GRB host galaxy at z = 3.967 is complex, with at…
Radiative transfer models in a spherical, turbulent interstellar medium (ISM) in which the photon source is situated at the center are calculated to investigate the correlation between the scattered light and the dust column density. The…
We study the absorption along lines of sight toward high-z radio sources caused by the 21 cm transition of neutral hydrogen in the intergalactic medium (IGM) before reionization. Using semi-analytic methods, we compute the number density of…
According to our present understanding, long GRBs originate from the collapse of massive stars while short bursts are due to the coalescence of compact stellar objects. Since the afterglow evolution is determined by the circumburst density…
Gamma-ray burst GRB221009A was of unprecedented brightness in gamma-rays and X-rays, and through to the far ultraviolet, allowing for identification within a host galaxy at redshift z=0.151 by multiple space and ground-based…
X-ray photons scattered by the interstellar medium carry information about dust distribution, dust grain model, scattering cross section, and the distance of the source; they also take longer time than unscattered photons to reach the…
Observations with the Swift satellite of X-ray afterglows of more than a hundred gamma ray bursts (GRBs) with known redshift reveal ubiquitous soft X-ray absorption. The directly measured optical depth \tau at a given observed energy is…
Using a radiative transfer code (DUSTY) parameters of the circumstellar dust shells of 15 hot post-AGB stars have been derived. Combining the optical, near and far-infrared (ISO, IRAS) data of the stars, we have reconstructed their spectral…
Small angle scatterings of X-rays by interstellar dust particles create halos around x-ray sources. By observing these halos with sufficient angular resolution it is possible to derive information about both the spatial distribution of the…
Long gamma-ray bursts are produced during the dramatic deaths of massive stars with very short lifetimes, meaning that they explode close to the birth place of their progenitors. During a short period they become the most luminous objects…
The complex structure of gas, metals, and dust in the interstellar and circumgalactic medium (ISM and CGM, respectively) in star-forming galaxies can be probed by Ly$\alpha$ emission and absorption, low-ionization interstellar (LIS) metal…
We present broad-band observations of the afterglow and environment of the short GRB 111020A. An extensive X-ray light curve from Swift/XRT, XMM-Newton and Chandra, spanning ~100 seconds to 10 days after the burst, reveals a significant…
We report the discovery of the host galaxy of dark burst GRB080607 at z_GRB=3.036. GRB080607 is a unique case of a highly extinguished (A_V~3 mag) afterglow that was yet sufficiently bright for high-quality absorption-line spectroscopy. The…
Dust in the host galaxies of gamma-ray bursts (GRBs) dims and reddens their afterglow spectra. Knowledge of the nature of this dust is crucial for correcting for extinction, providing clues to the nature of GRB progenitors, and probing the…
We present the first high resolution (R=20000--45000, corresponding to 14 km/s at 4200A to 6.6 km/s at 9000A) observations of the optical afterglow of Gamma Ray Bursts. GRB020813 and GRB021004 were observed by UVES@VLT 22.19 hours and 13.52…
We investigate the ability of high resolution X-ray spectroscopy to directly probe the grain composition of the interstellar medium. Using iron K-edge experimental data of likely ISM dust candidates taken at the National Synchrotron Light…
Observational follow-up of well localized short gamma-ray bursts (SGRBs) has left $20-30\%$ of the population without a coincident host galaxy association to deep optical and NIR limits ($\gtrsim 26$ mag). These SGRBs have been classified…