Dark matter gamma-ray line searches toward the Galactic Center halo with H.E.S.S. I

TL;DR

This paper reports a search for dark matter annihilation signals in gamma-ray data from the Galactic Center using H.E.S.S.-I, employing a 2D likelihood method to improve constraints on dark matter properties.

Contribution

It introduces a new analysis of a decade of H.E.S.S.-I data with a 2D likelihood approach, significantly tightening limits on dark matter annihilation cross sections.

Findings

No dark matter signal detected, leading to improved constraints.

Enhanced sensitivity achieved through combined spectral and spatial analysis.

Results set new upper limits on dark matter annihilation cross section.

Abstract

The presence of dark matter is nowadays widely supported by a large body of astronomical and cosmological observations. A large amount of dark matter is expected to be present in the central region of the Milky Way. Very-high-energy (>100 GeV) {\gamma}-rays can be produced in the annihilation of dark matter particles. The H.E.S.S. array of Imaging Atmospheric Cherenkov Telescopes is a powerful tools to observe the Galactic Centre trying to detect {\gamma}-rays from dark matter annihilation. A new search for a dark matter signal has been carried out on the full H.E.S.S.-I data set of 2004-2014 observations. A 2D-binned likelihood method has been applied to exploit the spectral and spatial properties of signal and background. Updated constraints are derived on the velocity-weighted annihilation cross section for signals from prompt annihilation of dark matter particles into two photons. The larger statistics from the 10-year Galactic Center dataset of H.E.S.S.-I together with the 2D-analysis technique allows to significantly improve the previous limits.