Radio confirmation of Galactic supernova remnant G308.3-1.4

Abstract

We present radio-continuum observations of the Galactic supernova remnant (SNR) candidate, G308.3-1.4, made with the Australia Telescope Compact Array, Molonglo Observatory Synthesis Telescope and the Parkes radio telescope. Our results combined with Chandra X-ray images confirm that G308.3-1.4 is a bona fide SNR with a shell morphology. The SNR has average diameter of D = 34 +- 19 pc, radio spectral index of alpha = -0.68 +- 0.16 and linear polarisation of 10 +- 1%; We estimate the SNR magnetic field B = 29 uG. Employing a Sigma-D relation, we estimate a distance to G308.3-1.4 of d = 19 +- 11 kpc. The radio morphology, although complex, suggests a smaller size for the SNR than previously implied in an X-Ray study. These results imply that G308.3-1.4 is a young to middle-aged SNR in the early adiabatic phase of evolution