Searching for Overionized Plasma in the Gamma-ray Emitting Supernova Remnant G349.7$+$0.2

TL;DR

This study investigates gamma-ray emission from supernova remnant G349.7+0.2, finding it is mainly from neutral pion decay and that the plasma is not overionized, providing insights into its particle acceleration and plasma state.

Contribution

The paper provides the first gamma-ray spectral analysis of G349.7+0.2, confirming hadronic origin of gamma rays and ruling out overionized plasma in this remnant.

Findings

Gamma-ray emission is dominated by neutral pion decay.

No evidence of overionized plasma in the remnant.

Protons follow a broken power-law distribution with a spectral break at ~12 GeV.

Abstract

G349.7$+$0.2 is a supernova remnant (SNR) expanding in a dense medium of molecular clouds and interacting with clumps of molecular material emitting gamma rays. We analyzed the gamma-ray data of Large Area Telescope on board Fermi Gamma Ray Space Telescope and detected G349.7$+$0.2 in the energy range of 0.2$-$300 GeV with a significance of $\sim$13$\sigma$ showing no extended morphology. Modeling of the gamma-ray spectrum revealed that the GeV gamma-ray emission dominantly originates from the decay of neutral pions, where the protons follow a broken power-law distribution with a spectral break at $\sim$12 GeV. To search for features of radiative recombination continua in the eastern and western regions of the remnant, we analyzed the Suzaku data of G349.7$+$0.2 and found no evidence for overionized plasma. In this paper we discuss possible scenarios to explain the hadronic gamma-ray emission in G349.7$+$0.2 and the mixed morphology nature of this SNR.