An investigation of radio supernova remnants and their environments

Abstract

In this thesis, I investigate the properties of emission from several supernova remnants (SNRs) and the connections of these observations to the properties of their progenitors, environments, and stages of evolution. I find that the highly-energetic pulsar B1338-62 near the centre of SNR G308.8-0.1 powers a pulsar wind nebula. I conclude that the unusual radio morphology of SNR G308.8-0.1 is best explained by the expansion of a young remnant into an environment with a strongly asymmetric density profile. The coincidence of an extraordinarily well-ordered magnetic field along one high surface-brightness section of SNR B0454-683 with a hydrogen cloud suggests that this segment of the remnant is well-evolved. In this interpretation, the strong compression of ambient magnetic fields by a non-adiabatic shock is responsible for the well-ordered magnetic field and high surface brightness. Using high sensitivity, high angular resolution follow-up observations, I detect the radio counterpart to the X-ray synchrotron shell of the young composite SNR G310.6-1.6. Additionally, I follow up three radio-selected SNR candidates and conclude that they are most likely extragalactic radio sources. I demonstrate that the radio source G296.593-0.975, previously considered an HII region, overlaps along the line-of-sight with middle-aged SNR G296.7-0.9.