A SEARCH FOR RADIO-LOUD SUPERNOVAE

Some extragalactic supernovae, such as SN 1986J in NGC 891 (Rupen et a l. 1987), are unusually strong radio sources. Their radio emission typ ically peaks a few years after the supernova explodes, and appears to arise from the interaction of the supernova shock with a dense stellar wind shed by the progenitor star. Since two radio-loud and possibly o ptically faint supernovae have recently been found serendipitously in nearby spiral galaxies, it is possible that such objects are common. I f so, this would have important consequences for our understanding of both the chemical enrichment history of galaxies and the radio emissio n from starburst galaxies. Preliminary results from a survey of nearby spiral galaxies with the Molonglo Observatory Synthesis Telescope (MO ST) allow us to make a first estimate of the radio supernova rate. A l arger study now in progress will provide a much more sensitive measure ment.