A Supernova Remnant Counterpart for HESS J1832-085

TL;DR

This paper reports the identification of a new supernova remnant, G23.11+0.18, with supporting gamma-ray data indicating it accelerates particles to TeV energies, and discusses its possible association with surrounding molecular gas structures.

Contribution

The study provides the first radio and gamma-ray evidence for G23.11+0.18 as a supernova remnant and a potential cosmic ray source, including morphological and spectral analysis.

Findings

Spectral index of -0.63 in 70-170MHz range

Gamma-ray detection supports SNR nature and particle acceleration

Molecular gas structures suggest progenitor wind bubble and hadronic gamma-ray production

Abstract

We examine the new Galactic supernova remnant (SNR) candidate, G23.11+0.18, as seen by the Murchison Widefield Array (MWA) radio telescope. We describe the morphology of the candidate and find a spectral index of -0.63+/-0.05 in the 70-170MHz domain. A coincident TeV gamma-ray detection in High-Energy Stereoscopic System (HESS) data supports the SNR nature of G23.11+0.18 and suggests that G23.11+0.18 is accelerating particles beyond TeV energies, thus making this object a promising new cosmic ray hadron source candidate. The remnant cannot be seen in current optical, infrared and X-ray data-sets. We do find, however, a dip in CO-traced molecular gas at a line-of-sight velocity of ~85 km/s, suggesting the existence of a G23.11+0.18 progenitor wind-blown bubble. Furthermore, the discovery of molecular gas clumps at a neighbouring velocity towards HESS J1832-085 adheres to the notion that a hadronic gamma-ray production mechanism is plausible towards the north of the remnant. Based on these morphological arguments, we propose an interstellar medium association for G23.11+0.18 at a kinematic distance of 4.6+/-0.8 kpc.