Multi-wavelength analysis of the Galactic supernova remnant MSH 11-61A

TL;DR

This study presents a multi-wavelength analysis of the supernova remnant MSH 11-61A, revealing its interaction with molecular clouds, detecting gamma-ray emission likely from hadronic processes, and characterizing its complex X-ray plasma states.

Contribution

It provides the first gamma-ray detection of MSH 11-61A and models its emission as predominantly hadronic, along with detailed X-ray plasma analysis.

Findings

Gamma-ray emission coincides with the remnant, likely from hadronic processes.

X-ray emission is from shock-heated ejecta with recombining plasma.

Remnant interacts with molecular clouds in the north and southwest.

Abstract

Due to its centrally bright X-ray morphology and limb brightened radio profile, MSH 11-61A (G290.1-0.8) is classified as a mixed morphology supernova remnant (SNR). H$\textsc{i}$ and CO observations determined that the SNR is interacting with molecular clouds found toward the north and southwest regions of the remnant. In this paper we report on the detection of $\gamma$-ray emission coincident with MSH 11-61A, using 70 months of data from the Large Area Telescope on board the \textit{Fermi Gamma-ray Space Telescope}. To investigate the origin of this emission, we perform broadband modelling of its non-thermal emission considering both leptonic and hadronic cases and concluding that the $\gamma$-ray emission is most likely hadronic in nature. Additionally we present our analysis of a 111 ks archival \textit{Suzaku} observation of this remnant. Our investigation shows that the X-ray emission from MSH 11-61A arises from shock-heated ejecta with the bulk of the X-ray emission arising from a recombining plasma, while the emission towards the east arises from an ionising plasma.