Introduction

The Australia Telescope is the premier imaging radio interferometer in the Southern hemisphere, and the only such modern instrument positioned able to observe SN 1987A. The compact array consists of six 22m antennas with a maximum baseline length of six kilometers. Additional Australian antennas can be combined with the Australia Telescope Compact Array (ATCA) for Very Long Baseline observations, but to date there are no detections of the supernova on baselines longer than six km. The data used for these images were taken on 21 October 1992 and 4-5 January 1993. The source was followed for a full 12 hour track each day, with a small amount of data rejected in periods of poor atmospheric phase stability.

Deconvolution in radio interferometry is more usually used to remove the far out side lobes caused by the incomplete sampling of the Fourier plane than for superresolution. While it has been known for many years that modest degrees of superresolution can be successful on simple sources, it is often the case that desired higher resolution can be obtained directly by using data from a different instrument, different array configuration, or different observing frequency. SN 1987A is unusual in that it is a crucially important object where higher resolution radio imaging data is simply not available. While the supernova will expand with time and thus provide a better look at the remnant to come, the existing data are all that will ever be obtained of the supernova at the current epoch of evolution. There is great incentive to extract as much spatial information as possible from the existing data. Even a map of very low dynamic range will be extremely valuable astrophysically, so long as the features interpreted are reliable.