Radio confirmation of Galactic supernova remnant G308.3-1.4

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 α = −0.68 ± 0.16 and linear polarization of 10 ± 1 per cent. We estimate the SNR to have a magnetic field of B ≈ 29 μG. Employing a∑-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.