Gamma-ray burst observations with H.E.S.S

TL;DR

This paper discusses the H.E.S.S. telescopes' efforts to detect very-high-energy gamma-ray emissions from gamma-ray bursts, aiming to explore their spectra and temporal evolution, which remain largely unknown due to their rapid fading.

Contribution

It introduces a dedicated GRB observing program with H.E.S.S. and reports observational results, advancing the search for VHE gamma-ray emission from GRBs.

Findings

No VHE gamma-ray emission detected from observed GRBs.

H.E.S.S. sensitivity is sufficient to detect predicted VHE flux levels.

Establishes observational constraints on GRB VHE emission models.

Abstract

The High Energy Stereoscopic System (H.E.S.S.) consists of four Imaging Atmospheric Cherenkov Telescopes (IACTs) in Namibia for the detection of cosmic very-high-energy (VHE) gamma-rays. Gamma-ray bursts (GRBs) are among the potential VHE gamma-ray sources. VHE gamma-emission from GRBs is predicted by many GRB models. Because of its generally fast-fading nature in many wavebands, the time evolution of any VHE gamma-radiation is still unknown. In order to probe the largely unexplored VHE gamma-ray spectra of GRBs, a GRB observing program has been set up by the H.E.S.S. collaboration. With the high sensitivity of the H.E.S.S. array, VHE gamma-ray flux levels predicted by GRB models are well within reach. We report the H.E.S.S. observations of and results from some of the reported GRB positions during March 2003 - May 2006.