# TeVPA 2018

27-31 August 2018
LVH, Luisenstraße 58, 10117 Berlin
Europe/Berlin timezone
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# Contribution Poster (A0 portrait)

LVH, Luisenstraße 58, 10117 Berlin -
Extragalactic

# GRB Observations with H.E.S.S II

## Speakers

• Ms. Ruiz-Velasco EDNA

## Abstract content

Fermi-LAT observations have proven that GeV gamma-ray emission is a relatively common feature for many gamma-ray bursts (GRBs). However, the relatively low effective area of space detectors implies low statistics for the highest energy photons which impedes detailed physical interpretation. The highest energy photon detected by LAT reached 95 GeV, a range which is well within reach for ground-based Imaging Atmospheric Cherenkov Telescopes (IACTs). As their effective area is orders of magnitude larger than that of Fermi-LAT, the IACT detection of high-energy gamma-rays from a GRB promises a wealth of detailed information. The High Energy Stereoscopic System (H.E.S.S.) is an IACT array belonging to the current generation of such instruments. It is the first hybrid IACT array composed of four 12 m diameter and one 28 m diameter telescopes. The large light collection area of 600 $m^2$ of the large telescope is perfectly suitable to observe gamma-rays between 50 GeV and 100 GeV with unprecedented sensitivity. Combined with the capability to rapidly and fully automatically react to alerts, H.E.S.S. is one of the most promising instruments to probe or constrain short time scale emission of GRBs at very high energies. In this contribution we will describe the H.E.S.S. GRB observation program, trigger conditions of GRB observations and analyses of several tens of GRBs. This compilation of observations represents the largest list of GRB observations with IACTs and provides numerous inputs for GRB modeling at very high energy.