CD8+ T cells employ granzyme B (GrB) to induce apoptosis in target cells. Increased expression of GrB has been put forward as a diagnostic marker in transplant rejection and viral infection. Three-color flow cytometric analysis revealed that peripheral blood CD8+ T lymphocytosis during primary cytomegalovirus infection after renal transplantation resulted from expansion of a CD8+GrB+CD62L+ T ce...

We present time resolved optical data acquired by the TAROT automated observatory on the afterglow of GRB 050525a from 6 to 136 min after the GRB. We find evidence for a rapid re-brightening of 0.65 mag of the afterglow at ∼33 min after the GRB. The decay slope α is 1.14 ± 0.07 in the first part and is 1.23 ± 0.27 after the re-brightening event. The afterglow of GRB 050525a is the third known a...

I review the use of ROSAT over the last years for the investigation of well localized gamma-ray burst (GRB) error boxes. In particular, I cover (i) the systematic study of several dozens of IPN locations using the ROSAT All-Sky-Survey data, (ii) results of deep ROSAT pointings of selected small GRB error boxes, (iii) the attempts for and results of quick follow-up observations after GRB events ...

We investigate the high-energy photon emission around Gamma-Ray Burst (GRB) remnants caused by ultrahigh-energy cosmic rays (UHECRs) from the GRBs. We apply the results to the recent report that the supernova remnant W49B is a GRB remnant in our Galaxy. If this is correct, and if GRBs are sources of UHECRs, a natural consequence of this identification would be a detectable TeV photon emission a...

The long GRB 050730 observed at redshift z ∼ 4 allowed the determination of the elemental abundances for a set of different chemical elements. We use detailed chemical evolution models taking into account also dust production to constrain the star formation history of the host galaxy of this long GRB. For the host galaxy of GRB 050730, we derive also some dustrelated quantities and the the spec...

The RAPid Telescopes for Optical Response (RAPTOR) system at Los Alamos National Laboratory observed GRB 050319 starting 25.4 seconds after γ-ray emission triggered the Burst Alert Telescope (BAT) on-board the Swift satellite. Our well sampled light curve of the early optical afterglow is composed of 32 points (derived from 70 exposures) that measure the flux decay during the first hour after t...

The EMBH model, previously developed using GRB 991216 as a prototype, is here applied to GRB 980425. We fit the luminosity observed in the 40–700 keV, 2–26 keV and 2–10 keV bands by the BeppoSAX satellite. In addition we present a novel scenario in which the supernova SN1998bw is the outcome of an " induced gravitational collapse " triggered by GRB 980425, in agreement with the GRB-Supernova Ti...

We study the chemical abundances of the interstellar medium surrounding high z gamma-ray bursts (GRBs) through analysis of the damped Lyα systems (DLAs) identified in afterglow spectra. These GRB-DLAs are characterized by large H I column densities NHI and metallicities [M/H[ spanning 1/100 to nearly solar, with median [M/H[ > −1 dex. The majority of GRB-DLAs have [M/H[ values exceeding the cos...

Since January 1997, we have monitored 15 GRB fields, detecting 6 optical/IR afterglows. We have revisited GRB 970508 and GRB 980326. For GRB 970508, we derive a power-law decay exponent α =-1.19 (R-band). The luminosity of the host galaxy L relative to the characteristic luminosity L ⋆ is in the range 0.06–0.15, i.e. a dwarf galaxy. For GRB 980326, we derive a power-law decay exponent α =-1.7, ...