High - resolution radio observations of RCW 49

High-resolution radio continuum observations of the southern H II complex RCW 49 are presented. The observations were carried out with the Molonglo Observatory Synthesis Telescope (MOST) at 0.843 GHz, and the Australia Telescope Compact Array (ATCA) at 1.38 and 2.38 GHz. Two wind-blown shells have been discovered in the core region of RCW 49, the more massive of which surrounds the Westerlund 2 cluster and exhibits a remarkable blister structure. The second shell, surrounding the recently-discovered star WR20b, is an example of a Wolf-Rayet ring nebula.