A Radio Study of Selected Regions in the Magellanic Clouds

Abstract

The Magellanic Clouds have long provided a rich celestial laboratory for many astrophysical research programmes. Their location relatively close to the Earth and away from the plane of our Galaxy has made them a natural target for Southern Hemisphere ground-based instrumentation. Likewise, the continuing quest for images of the Clouds with higher dynamic range and improved angular resolution has driven a continual improvement in instrumentation across a range of wavelength bands. The cornerstone of this thesis is a study of selected sources in the Magellanic Clouds. The sample was chosen from the 843MHz Molonglo Observatory Synthesis Telescope survey of the Clouds, based on the existing knowledge of each source, its flux density and angular extent. This sample was used to explore observational and analysis techniques with the Australia Telescope Compact Array in order to better determine the nature of these objects and to identify those sources worthy of further study. This work highlights many pertinent issues associated with the correct classification of sources when only a limited amount of data is available. These issues led directly to the development of a more systematic approach in the classification of the Large Magellanic Cloud source sample, detailed for the first time in this thesis. Two supernova remnants in the Small Magellanic Cloud were studied in detail. The Australia Telescope images of 1E0102.2-7219 revealed, for the first time, the radio structure of this young oxygen-rich supernova remnant, and allowed a detailed comparison with existing optical and X-ray data to be undertaken. The comparisons presented in this thesis and in an earlier publication have prompted exciting new X-ray observations at unprecedented angular resolution. The second, 0101-7226, studied as part of an international collaboration, has a shell morphology at radio wavelengths but no associated X-ray emission and is therefore something of an enigma.