Investigating the X-ray and Gamma-ray Properties of the Galactic Supernova Remnants Kes 69, 3C 396, 3C 400.2

TL;DR

This study analyzes X-ray and gamma-ray data of three mixed-morphology supernova remnants, revealing recombining plasma features and gamma-ray emissions, which suggest interactions with molecular clouds and potential cosmic ray acceleration.

Contribution

It provides new evidence of recombining plasma in 3C 400.2 and gamma-ray detections in Kes 69 and 3C 396, advancing understanding of SNR-MC interactions.

Findings

Recombining plasma detected in 3C 400.2

Gamma-ray emission observed from Kes 69 and 3C 396

X-ray emission from 3C 400.2's NW and SE regions is from recombining plasma

Abstract

Kes 69, 3C 396, and 3C 400.2 are mixed-morphology (MM) Galactic supernova remnants (SNRs), where Kes 69 and 3C 396 are interacting with molecular clouds (MCs). Previous X-ray studies showed that the emission from these SNRs is thermal. It has been suggested that MM SNRs interacting with MCs are potential candidates for recombining plasma (RP) in X-rays and hadronic gamma-ray emission. Recently, Chandra observations revealed signs of RP in 3C 400.2. Our preliminary analyses show that the X-ray emission of NW and SE region of 3C 400.2 arises from recombining plasma. We detected GeV gamma-ray emission from Kes 69 and 3C 396 above 5$\sigma$.