AN HI MOSAIC OF THE SMALL MAGELLANIC CLOUD

This paper describes the first results from a 20 deg(2) mosaic of the Small Magellanic Cloud (SMC) in the lambda 21-cm line of neutral hydro gen. The mosaic consists of 320 separate pointings with the 375-m arra y of the Australia Telescope Compact Array. The angular resolution is 1'.5 (26 pc, for a distance of 60 kpc) and the velocity resolution is 1.6 kms(-1). The images reveal a structure of remarkable complexity, w ith much of the spatial power contained in high-brightness temperature compact knots and filaments. Numerous wind-blown 'bubbles' and 'super shells' are evident in the data, both inside and outside the stellar c onfines of the SMC. Some high-density HI regions are seen to correlate with Her regions, indicating sites of current star formation. However , many high-column-density HI regions are devoid of optical emission a nd may represent regions of future star formation. These regions may b e under-abundant in diffuse molecular gas due to the high radiation fi eld and low metallicity of the SMC.