Sgr A* Observations with H.E.S.S. II

TL;DR

This paper presents new H.E.S.S. II observations of the Galactic Centre, revealing detailed gamma-ray morphology and extending the energy range down to 100 GeV, enhancing understanding of cosmic-ray acceleration near Sgr A*.

Contribution

It introduces the use of the fifth H.E.S.S. telescope to observe the Galactic Centre at lower energies, providing more detailed gamma-ray data and comparisons with other wavelengths.

Findings

Detection of gamma-ray emission down to 100 GeV

Detailed morphology of the central gamma-ray source

Insights into cosmic-ray acceleration processes

Abstract

The Galactic Centre has been studied with the High Energy Stereoscopic System (H.E.S.S.) for over 10 years, revealing a bright, complex gamma-ray morphology. Besides a strong point-like very-high-energy gamma-ray source coincident with the supermassive black hole Sgr A*, pre- vious analyses also revealed a diffuse ridge of gamma-ray emission, indicative of a powerful cosmic-ray accelerator in this region. The addition of a fifth telescope with 600 m 2 mirror area to the centre of the H.E.S.S. array has increased the energy range accessible, allowing observations to take place down to 100 GeV and potentially below. This wider energy range allows an important overlap in observations with satellite instruments such as the Fermi-LAT gamma-ray telescope. We will present the results of new H.E.S.S observations of the Galactic Centre region and show a detailed analysis of the central source, including comparisons to results at other wavelengths.