ar X iv : a st ro - p h / 04 09 71 7 v 2 1 4 Fe b 20 05 A flash in the dark : UVES / VLT high resolution spectroscopy of GRB afterglows

ar X iv : a st ro - p h / 03 02 17 7 v 1 1 0 Fe b 20 03 Polarization in GRB Afterglows

Se p 20 04 A flash in the dark : UVES / VLT high resolution spectroscopy of GRB afterglows

We present the first high resolution (R=20000–45000, corresponding to 14 km/s at 4200Å to 6.6 km/s at 9000Å ) observations of the optical afterglow of Gamma Ray Bursts. GRB020813 and GRB021004 were observed by UVES@VLT 22.19 hours and 13.52 hours after the trigger, respectively. These spectra show that the inter–stellar matter of the GRB host galaxies is complex, with many components contributi...

ar X iv : a st ro - p h / 05 09 42 4 v 1 1 5 Se p 20 05 Multi - Wavelength Studies of the Optically Dark Gamma - Ray Burst 001025 A

We identify the fading X-ray afterglow of GRB 001025A from XMM-Newton observations obtained 1.9–2.3 days, 2 years, and 2.5 years after the burst. The non-detection of an optical counterpart to an upper limit of R = 25.5, 1.20 days after the burst, makes GRB 001025A a " dark " burst. Based on the X-ray af-terglow spectral properties of GRB 001025A, we argue that some bursts appear – 2 – opticall...

ar X iv : a st ro - p h / 02 09 51 6 v 1 2 4 Se p 20 02 High Resolution Grating Spectroscopy of GRB 020405 with CHANDRA LETGS

We present high-resolution X-ray spectroscopy of GRB 020405 obtained with the Low Energy Transmission Grating Spectrometer (LETGS) on board the Chan-dra X-ray Observatory starting 1.68 days after the burst. The spectrum appears featureless, with no evidence for emission lines, absorption edges, or narrow ra-diative recombination continua. The continuum can be fitted by a power law of photon ind...

ar X iv : a st ro - p h / 06 01 25 3 v 1 1 1 Ja n 20 06 1 A VLT / UVES SPECTROSCOPIC ANALYSIS OF C - RICH FE - POOR STARS

Large surveys of very metal-poor stars have revealed in recent years that a large fraction of these objects were carbon-rich, analogous to the more metal-rich CH-stars. The abundance peculiarities of CH-stars are commonly explained by mass-transfer from a more evolved companion. In an effort to better understand the origin and importance for Galactic evolution of Fe-poor, C-rich stars, we prese...