Discovery of the radio and X-ray counterpart of TeV Gamma-ray source HESS J1731-347

TL;DR

This paper reports the discovery of a faint shell-type radio and X-ray source, G353.6-0.7, identified as an old supernova remnant that is associated with the TeV gamma-ray source HESS J1731-347, providing evidence of old SNRs emitting TeV gamma-rays.

Contribution

The study identifies G353.6-0.7 as an old supernova remnant associated with a TeV gamma-ray source, establishing a link between old SNRs and TeV gamma-ray emission.

Findings

G353.6-0.7 is a likely old supernova remnant.

The SNR is associated with HESS J1731-347 and diffuse X-ray emission.

The SNR is approximately 27,000 years old.

Abstract

We discover a faint shell-type radio and X-ray source, G353.6-0.7, associated with HESS J1731-347. G353.6-0.7 is likely an old supernova remnant (SNR), based on radio (0.8 GHz, 1.4 GHz and 5 GHz), infrared (8 $\mu$m from the GLIMPSE Legacy Project and 21 $\mu$m from the Midcourse Space Experiment), and X-ray (0.1 keV - 2.4 keV from the ROSAT survey and 5 - 20 keV from the INTEGRAL survey) data. The SNR, centered at ({\sl l}, {\sl b})=(353.55, -0.65) with a radius of $\sim$ 0.25$^{\circ}$, closely matches the outline of the recently discovered extended TeV source HESS J1731-347, which has no previously identified counterpart. A diffuse X-ray enhancement detected in the ROSAT all-sky survey is coincident with lower half shell of the SNR. Therefore the SNR is the best radio counterpart of both the HESS source and the diffuse X-ray enhancement. G353.6-0.7 has an age of $\sim$ 27000 yrs. Altogether, the new discovery provides the best case that an old SNR emits TeV $\gamma$-rays.