Gravitational wave alert follow-up strategy in the H.E.S.S. multi-messenger framework

Abstract: The H.E.S.S. high-energy gamma-ray observatory is member of the Virgo/LIGO electromagnetic follow-up effort since early 2014. Its capability for transient follow-up studies benefits from its large field of view, rapid response time and high sensitivity. Drawing from the experience gained from other science cases like gamma-ray bursts and high-energy neutrino follow-ups we demonstrate the high perspectives for new types of analyses like the search for gravitational wave counterparts and the study of multi-messenger signals from binary neutron star mergers. This contribution aims to present the potential pointing strategy that the H.E.S.S. observatory would carry out following an alert from gravitational wave observatories. We will discuss several key points like the use of information from a galaxy catalogue, the time-dependent visibility of sky regions and the automatic handling of gravitational wave uncertainty maps, that will enable an optimized choice of the pointing directions. Finally, based on simulated binary neutron star mergers, the performance of the outlined gravitational wave-alert observations will be presented.