Observations of Binary Systems with the H.E.S.S. Telescopes

TL;DR

This paper reports on recent H.E.S.S. telescope observations of binary systems, including spectral analysis, long-term monitoring, and the search for gamma-ray emissions, providing new insights into high-energy astrophysical phenomena.

Contribution

It presents new observational data and analysis of multiple binary systems at very high energies, including the first H.E.S.S. II spectra of PSR B1259-63 and extended observations of LS 5039.

Findings

H.E.S.S. II spectra of PSR B1259-63 down to 200 GeV

Extended spectral energy distribution of LS 5039 down to 120 GeV

Constraints on gamma-ray flux from microquasars GRS 1915+105, Circinus X-1, and V4641 Sgr

Abstract

Observations of binary systems obtained recently with the High Energy Stereoscopic System (H.E.S.S) of Cherenkov telescopes are reported. The outcomes of a detailed observation campaign on PSR B1259-63 during its periastron passage in 2014 will be presented. This system was observed for the first time with H.E.S.S. II, providing spectra and light curves down to 200 GeV, which will be compared with observations conducted during previous periastron passages and with results from an analysis of contemporaneously taken Fermi-LAT data. Also long-term observations of LS 5039 with H.E.S.S in phase I and phase II are reported. This source was monitored at very high energies (VHEs) in a period of time spanning more than ten years. Its spectral energy distribution measured with H.E.S.S. II extends down to 120 GeV. Spectral results from the Fermi-LAT observations are shown as well, and the compatibility with H.E.S.S. results in the overlapping energy range is discussed. The identification of the new gamma-ray binary candidate HESS J1832-093 will also be presented. Furthermore, the search for VHE emission from the microquasars GRS 1915+105, Circinus X-1 and V4641 Sgr based on data from H.E.S.S. observations conducted contemporaneously with the RXTE satellite experiment will be reported. These data provide constraints on the integral gamma-ray flux at different X-ray states of the three sources.