Survey of the Magellanic Clouds at 4.8 and 8.64 GHz

Abstract

Detailed 4.8 and 8.64 GHz radio images of the entire Large and Small Magellanic Clouds with half-power beamwidths of 35″ at 4.8 GHz and 22″ at 8.64 GHz have been obtained using the Australia Telescope Compact Array. Full polarimetric observations were made. Several thousand mosaic positions were used to cover an area of 6° on a side for the LMC and 4.5° for the SMC. These images have sufficient spatial resolution (~ 8 and 5 pc, respectively) and sensitivity (3σ of 1.5 mJy beam⁻¹) to identify most of the individual supernova remnants and H ii regions and also, in combination with available data from the Parkes 64-m telescope, the structure of the smooth emission in these galaxies. We have recently revised the early data analysis (Dickel et al. 2005) by increasing the CLEAN cutoff limit to recover more intermediate-spacing data and thus present more accurate brightnesses for extended sources. In addition, limited data using the sixth antenna at 4.5 – 6 km baselines are available to distinguish bright point sources (< 3″ and 2″, respectively) and to help estimate sizes of individual sources smaller than the resolution of the full survey. The resulting database will be valuable for statistical studies and comparisons with X-ray, optical, and infrared surveys of the LMC with similar resolution.