A Search for Isolated Microwave Pulses from the Perseus Cluster of Galaxies

An experiment designed to search for prompt microwave bursts from supernovae (SN) in the Coma cluster of galaxies has already been described elsewhere (Jelley et al., 1974, subsequently referred to as Paper I). We present here the results from extended observations at five widely separated sites, on the central region of the Perseus cluster of galaxies, along with a calibration carried out on Solar flares. Colgate and Noerdlinger (1971) predicted, from the original shock-wave model of supernovae (Colgate and White, 1966), that prompt bursts of radio emission would be expected from supernova explosions. LeBlanc and Wilson (1970) show, on a different model of stellar collapse, that large amounts of energy in various forms may be released in periods ,.., 0.1 3 s. It is not however clear in this model that the energy can escape through the outer layers of the star. Our sensitivity is such that we could have detected a pulse having an energy over the entire microwave spectrum (taken arbitrarily to be 3-30 GHz) of 8.8 x 10-s of an assumed total prompt energy release in a SN of ,.., 10 51 erg, if this were at the distance of the Perseus cluster. This figure is deduced on the assumption of a flat spectrum. and no supernovae were reported during this period from the optical surveys, in that region of sky.