Likely GeV emission from an old Supernova Remnant: SNR G206.9+2.3

TL;DR

This study reports the first detection of GeV gamma-ray emission from the supernova remnant G206.9+2.3 using 12.4 years of Fermi-LAT data, suggesting it as a likely gamma-ray source associated with the remnant.

Contribution

First identification of gamma-ray emission from SNR G206.9+2.3, providing insights into its high-energy properties and possible emission mechanisms.

Findings

Detected gamma-ray emission with flux (1.19±0.59)×10^{-9} cm^{-2} s^{-1}

Spectral index of 2.22±0.19 in 0.2-500 GeV band

Spatial correlation with radio observations

Abstract

A novel $\gamma$-ray supernova remnant (SNR) G206.9+2.3 is first reported in this study. We arrived at this conclusion after analyzing 12.4 years of observation data of the Fermi Large Area Telescope (Fermi-LAT). The photon flux of the remnant was (1.19$\pm$0.59) 10$^{-9}$ cm$^{-2}$ s$^{-1}$, and its power-law spectral index was 2.22$\pm$0.19 in the 0.2-500 GeV energy band. Moreover, we found that the test statistic values of the global fit from the four different energy bands were greater than 9. We identified that this was a real $\gamma$-ray signal. Furthermore, we found that its GeV spatial location was in good agreement with that of its radio band. Its spectral energy distribution and light curve properties were similar to those of SNRs. We suggest that the novel $\gamma$-ray source is a likely counterpart to SNR G206.9+2.3. Consequently, we discuss its likely leptonic or hadronic origin.