Unique data on BV RI brightness curves of the OT of GRB 970508 obtained with the 6-m telescope have been interpreted in the framework of the GRB-SN (supernovae) connection. The effect must be maximal in the Ic band as OT GRB 970228 [5]. The peak absolute (MB) magnitude of the suggested SN must be around -19.5 for the OT of GRB 970508. If all or the main part of long GRBs are associated with SNe...

We report on near-infrared and optical observations of the GRB 970616 error box and of the X-ray sources discovered by ASCA and ROSAT in the region. No optical transient was found either within the IPN band or in the X-ray error boxes, similarly to other bursts, and we suggest that either considerable intrinsic absorption was present (like GRB 970828) or that the optical transient displayed a v...

Lymphocyte granule-mediated apoptosis occurs by perforin-mediated intracellular delivery of granule-associated serine proteases (granzymes). A granule-associated proteoglycan, namely serglycin, that contains chondroitin 4-sulfate (CS) glycosaminoglycans is present in the granules of cytotoxic cells. Serglycin acts as scaffold for packaging the positively charged granzymes and probably chaperone...

We present the largest, publicly available, sample of Damped Lyman-α systems (DLAs) along Swift discovered Gamma-ray Bursts (GRB) line of sights in order to investigate the environmental properties of long GRB hosts in the z = 1.8− 6 redshift range. Compared with the most recent quasar DLAs sample (QSO-DLA), our analysis shows that GRB-DLAs probe a more metal enriched environment at z 3, up to ...

Context. GRB060614 observations by VLT and by Swift have infringed the traditionally accepted gamma-ray burst (GRB) collapsar scenario that purports the origin of all long duration GRBs from supernovae (SN). GRB060614 is the first nearby long duration GRB clearly not associated with a bright Ib/c SN. Moreover, its duration (T90 ∼ 100 s) makes it hardly classifiable as a short GRB. It presents s...

We model the radio, optical, and X-ray emission for the afterglows of GRB 980703, 990123, 990510, and 991216, within the framework of relativistic jets, to determine the physical parameters of these afterglows. For the last three we find jet energies around 10 ergs and initial opening angles less than 3 deg. The external medium density obtained from fits to the data ranges from 10 cm to less th...

The supernova SN 2006aj associated with GRB 060218 is the second-closest GRB-SN observed to date (z=0.033) and is the clearest example of a SN associated with a Swift GRB with the earliest optical spectroscopy. Its optical data showed that this is the fastest evolving and among the least luminous GRB-SNe (70% as luminous as SN1998bw). However, its expansion velocity and a comparison with other ...

We review the observational status of the supernova/gamma-ray burst connection. Present data suggest that SNe associated with GRBs form a heterogeneous class of objects including both bright and faint hypernovae and perhaps also ‘standard’ Ib/c events. Evidence for association with other types of core-collapse SNe (e.g. IIn) is much weaker. After combining the local GRB rate with the local SN-I...

We study here the Gamma-Ray Burst (GRB) environment through the analysis of the optical absorption features due to the gas surrounding the GRB. In particular, we analyze high resolution spectroscopic observations of GRB080319B and GRB080330 taken with UVES at the VLT, starting 8m30s and 1.5hr after the GRB trigger, respectively. The spectra show that the ISM of the GRB host galaxies are complex...

Taking into account the recent suggestion that a short gamma-ray burst (GRB) looks like the first 1 sec of a long GRB, we propose that the jet of a GRB consists of multiple sub-jets or sub-shells (i.e., an inhomogeneous jet model). The multiplicity of the sub-jets along a line of sight ns is an important parameter. If ns is large (≫ 1) the event looks like a long GRB, while if ns is small (∼ 1)...