Discovery of the VHE gamma-ray source HESS J1832-093 in the vicinity of SNR G22.7-0.2

TL;DR

This paper reports the discovery of a new VHE gamma-ray source near SNR G22.7-0.2, with potential origins including cosmic-ray interactions, a pulsar wind nebula, or a binary system, based on multi-wavelength observations.

Contribution

The study identifies a new VHE gamma-ray source and explores its possible origins, combining gamma-ray, X-ray, and radio data to propose multiple scenarios.

Findings

Discovery of HESS J1832-093 near SNR G22.7-0.2

Spectral analysis shows a power-law with index 2.6

Identification of a new X-ray point source coincident with the gamma-ray emission

Abstract

The region around the supernova remnant (SNR) W41 contains several TeV sources and has prompted the H.E.S.S. Collaboration to perform deep observations of this field of view. This resulted in the discovery of the new very high energy (VHE) source HESS J1832-093, at the position $\rm RA=18^h 32^m 50^s \pm 3^s_{stat} \pm 2^s_{syst}, \rm Dec=-9^\circ 22' 36'' \pm 32''_{stat} \pm 20''_{syst} (J2000)$, spatially coincident with a part of the radio shell of the neighboring remnant G22.7-0.2. The photon spectrum is well described by a power-law of index $\Gamma = 2.6 \pm 0.3_{\rm stat} \pm 0.1_{\rm syst}$ and a normalization at 1 TeV of $\Phi_0=(4.8 \pm 0.8_{\rm stat}\pm 1.0_{\rm syst})\,\times\,10^{-13}\,\rm{cm} ^{-2}\,s^{-1}\,TeV^{-1}$. The location of the gamma-ray emission on the edge of the SNR rim first suggested a signature of escaping cosmic-rays illuminating a nearby molecular cloud. Then a dedicated XMM-Newton observation led to the discovery of a new X-ray point source spatially coincident with the TeV excess. Two other scenarios were hence proposed to identify the nature of HESS J1832-093. Gamma-rays from inverse Compton radiation in the framework of a pulsar wind nebula scenario or the possibility of gamma-ray production within a binary system are therefore also considered. Deeper multi-wavelength observations will help to shed new light on this intriguing VHE source.