Discovery of a VHE gamma-ray source coincident with the supernova remnant CTB 37A

TL;DR

This paper reports the discovery of a new very high energy gamma-ray source coincident with supernova remnant CTB 37A, providing insights into cosmic ray acceleration and gamma-ray production mechanisms.

Contribution

The study presents the first detection of VHE gamma-ray emission from CTB 37A and analyzes its spectral and spatial properties in relation to molecular clouds and X-ray counterparts.

Findings

VHE gamma-ray source HESS J1714-385 coincides with CTB 37A.

The gamma-ray spectrum follows a power-law with index 2.30.

The VHE flux is about 3% of the Crab nebula flux above 1 TeV.

Abstract

The supernova remnant (SNR) complex CTB 37 is an interesting candidate for observations with Very High Energy (VHE) gamma-ray telescopes such as H.E.S.S. In this region, three SNRs are seen. One of them is potentially associated with several molecular clouds, a circumstance that can be used to probe the acceleration of hadronic cosmic rays. This region was observed with the H.E.S.S. Cherenkov telescopes and the data were analyzed with standard H.E.S.S. procedures. Recent X-ray observations with Chandra and XMM-Newton were used to search for X-ray counterparts. The discovery of a new VHE gamma-ray source HESS J1714-385 coincident with the remnant CTB 37A is reported. The energy spectrum is well described by a power-law with a photon index of Gamma =2.30pm0.13 and a differential flux at 1 TeV of Phi_0 = (8.7 pm 1.0_{stat} pm 1.8_{sys})x10^{-13}cm^{-2}s^{-1}TeV^{-1}. The integrated flux above 1 TeV is equivalent to 3% of the flux of the Crab nebula above the same energy. This VHE gamma-ray source is a counterpart candidate for the unidentified EGRET source 3EG J1714-3857. The observed VHE emission is consistent with the molecular gas distribution around CTB 37A; a close match is expected in a hadronic scenario for gamma-ray production. The X-ray observations reveal the presence of thermal X-rays from the NE part of the SNR. In the NW part of the remnant, an extended non-thermal X-ray source, CXOU J171419.8-383023, is discovered as well. Possible connections of the X-ray emission to the newly found VHE source are discussed.