G321.3--3.9: A new supernova remnant observed with multi-band radio data and in the SRG/eROSITA All-Sky Surveys

Abstract

was first identified as a partial shell at radio frequencies a few decades ago. Although it continued to be observed, no additional studies were undertaken until recently. In this paper we present results from a large selection of radio and X-ray data that cover the position of We confirmed as a new supernova remnant (SNR) using data collected by several radio surveys, spanning a frequency range from 200 to 2300\,MHz. Stacked eROSITA data from four consecutive all-sky surveys (eRASS:4) provide spectro-imaging information in the energy band $0.2-8.0$ keV. has an elliptical shape with major and minor axes of approximately $1 From CHIPASS and S-PASS data, we calculate a spectral index $ 0.2$, consistent with synchrotron emission from an expanding shell in the radiative phase. The eROSITA data show an X-ray diffuse structure filling almost the entire radio shell. Based on our spectral analysis, we found the temperature to be approximately 0.6 keV and the column absorption density about $ cm$^ $. Comparing this absorption density to optical extinction maps, we estimated the distance to fall within the range of (1.0 -- 1.7) kpc, considering the $1 uncertainty range.