%0 Generic
%A Tam, Pak Hin
%D 2008
%F heidok:9034
%K GammastrahlenblitzeAstrophysics, High-energy astronomy , Cherenkov radiation , Gamma-ray bursts
%R 10.11588/heidok.00009034
%T Gamma-ray burst studies using the H.E.S.S. Cherenkov array
%U https://archiv.ub.uni-heidelberg.de/volltextserver/9034/
%X Gamma-ray bursts (GRBs) are the most intense and unpredictable gamma-ray events from the Universe. Without prior signal, an enormous amount of energy is released for seconds, energizing particles and generating the observed 10e5-10e6 eV gamma-ray photons. The emitting regions can produce Very-High-Energy (VHE) gamma-ray photons of energy about 10e11 eV during and after the burst. These VHE gamma-rays may be attenuated in the source or by the extragalactic background light (EBL). The H.E.S.S. array of four imaging atmospheric Cherenkov telescopes (IACT) is sensitive to VHE gamma-rays. H.E.S.S. observations of 34 GRBs were carried out during 2003-2008, with the shortest response time being six minutes. No evidence of VHE gamma-rays was found. Flux upper limits derived for GRB030329 and GRB060505 are compared and are found consistent with the synchrotron self-Compton flux calculated in the context of relativistic blast-wave model. Absorption by EBL was taken into consideration. Accidentally, GRB060602B was observed with H.E.S.S. throughout the GRB duration, during which no signal of VHE gamma-rays was found. The distance scale and origin of GRB060602B remain unclear and different possibilities and implications are presented. Future prospects of VHE gamma-ray observations of GRBs are discussed.
%Z Teile in: The Astrophysical Journal, 10.1088/0004-637X/690/2/1068