Dark Matter searches with H.E.S.S. towards dwarf spheroidal galaxies

TL;DR

This paper reviews H.E.S.S. observations of dwarf spheroidal galaxies to search for gamma-ray signals from Dark Matter annihilation, setting constraints on particle properties and exploring flux enhancement effects.

Contribution

It provides the first comprehensive review of H.E.S.S. dwarf galaxy observations and derives new constraints on Dark Matter annihilation cross-sections.

Findings

No clear gamma-ray signals detected.

Constraints placed on Dark Matter particle models.

Studied potential flux enhancements like Sommerfeld effect.

Abstract

The H.E.S.S. experiment is an array of four identical imaging atmospheric Cherenkov telescopes in the Southern hemisphere, designed to observe very high energy gamma-rays (E > 100 GeV). These high energy gamma-rays can be used to search for annihilations of Dark Matter particles in dense environments. Dwarf galaxy dynamics shows that they are Dark Matter-dominated environments. Several observation campaigns on dwarf satellite galaxies of the Milky Way were launched by H.E.S.S.. The observations are reviewed. In the absence of clear signals, constraints on the Dark Matter particle annihilation cross-section have been derived in different particle physics scenarios. Some possible enhancements of the gamma-ray flux are studied, i.e., the Sommerfeld effect, the internal bremsstrahlung and the substructures in the Dark Matter halo.