Fermi-LAT detection of GeV $\gamma$-ray emission from Type Ia supernova remnant G272.2-3.2

Abstract

A new $\gamma$-ray source with a significance level of approximately 5$\sigma$ was reported in the region of SNR G272.2-3.2, analysing the approximately 12.4 years of observation data from the Fermi Large Area Telescope (Fermi-LAT). Its $\gamma$-ray spatial distribution did not show extended feature, and it had a soft spectrum with the spectral index of 2.56$\pm$0.01 of a power-law model. No significant variability of its light curve (LC) with 10 time bins was identified, and its spatial positions in the X-ray and GeV bands overlapped. We suggest that the new $\gamma$-ray source is a likely counterpart of SNR G272.2-3.2. Analysing its spectrum, we discussed the likely origins of the $\gamma$-ray emission.