Related papers: The properties of the 2175AA extinction feature di…
The UV extinction feature at 2175 \AA\ is ubiquitously observed in the Galaxy but is rarely detected at high redshifts. Here we report the spectroscopic detection of the 2175 \AA\ bump on the sightline to the \gamma-ray burst (GRB)…
We report the clear detection of the 2175A dust absorption feature in the optical afterglow spectrum of the gamma-ray burst (GRB) GRB070802 at a redshift of z=2.45. This is the highest redshift for a detected 2175A dust bump to date, and it…
GRB afterglows are well suited to extinction studies due to their brightness, simple power-law spectra and the occurrence of GRBs in distant star forming galaxies. In this paper we present results from the SED analysis of a sample of 41 GRB…
We explore the extinction properties of the dust in the distant universe through the afterglows of high-redshifted GRBs based on the "Drude" model which, unlike previous studies, does not require a prior assumption of template extinction…
We present optical photometry of the GRB 060912A afterglow obtained with ground-based telescopes, from about 100 sec after the GRB trigger till about 0.3 day later, supplemented with the Swift optical afterglow data released in its official…
We present optical and near-infrared photometry of the afterglow of the long Gamma-Ray Burst GRB 070802 at redshift 2.45 obtained with the ESO/MPI 2.2 m telescope equipped with the multi-channel imager GROND. Follow-up observations in…
Using a sample of gamma-ray burst (GRB) afterglows detected by both the X-Ray and the UV/Optical Telescopes (XRT and UVOT) on Swift, we modelled the spectral energy distributions (SEDs) to determine gas column densities and dust extinction…
Extinction curves contain key information on interstellar dust composition and size distribution, with the 2175 {\AA} bump being the most prominent feature. We analyze 20 sightlines toward M31 using HST/STIS UV spectroscopy combined with…
We determine the extinction curve in the z_l=0.83 lens galaxy of the gravitational lens SBS0909+532 from the wavelength dependence of the flux ratio between the lensed quasar images (z_s=1.38) from 3400 to 9200\AA. It is the first…
We present early-time optical through infrared photometry of the bright gamma-ray burst GRB 080607, starting only 6 s following the initial trigger in the rest frame. Complemented by our previously published spectroscopy, this high-quality…
We use a new approach to obtain limits on the absorbing columns towards an initial sample of 10 long Gamma-Ray Bursts observed with BeppoSAX and selected on the basis of their good optical and nIR coverage, from simultaneous fits to nIR,…
We present the spectroscopic and photometric late-time follow-up of the host galaxy of the long-duration Swift gamma-ray burst GRB 140506A at z = 0.889. The optical and near-infrared afterglow of this GRB had a peculiar spectral energy…
We present photometric and spectroscopic observations of the extraordinary gamma-ray burst (GRB) 221009A in search of an associated supernova. Some past GRBs have shown bumps in the optical light curve that coincide with the emergence of…
The Small Magellanic Cloud (SMC) shows a large variation in ultraviolet (UV) dust extinction curves, ranging from Milky Way-like (MW) to significantly steeper curves with no detectable 2175 A bump. This result is based on a sample of only…
To investigate the properties of dust in the nuclear region of quasars, we explored the extinction curves of the iron low-ionization broad absorption line (FeLoBAL) quasar SDSS J163004.29+311957.6 and its two analogues. The parameterized…
We present a proof-of-concept study that dust extinction curves can be extracted from the infrared (IR), optical, ultraviolet (UV) and X-ray afterglow observations of GRBs without assuming known extinction laws. We focus on GRB 050525A (z =…
GRB 220627A is a rare burst with two distinct gamma-ray emission episodes separated by almost 1000 s that triggered the Fermi Gamma-ray Burst Monitor twice. High-energy GeV emission was detected by the Fermi Large Area Telescope coincident…
The brightness of gamma-ray burst (GRB) afterglows and their occurrence in young, blue galaxies make them excellent probes to study star forming regions in the distant Universe. We here elucidate dust extinction properties in the early…
In this work we use gamma-ray burst (GRB) afterglow spectra observed with the VLT/X-shooter spectrograph to measure rest-frame extinction in GRB lines-of-sight by modeling the broadband near-infrared (NIR) to X-ray afterglow spectral energy…
We present low-resolution VLT spectroscopy of the afterglow of the gamma-ray bursts (GRBs) 991216, 011211 and 021211. Our spectrum of GRB991216 is the only optical spectrum for this afterglow. It shows two probable absorption systems at…