A model for the radio brightness of the supernova remnant 1987A

Abstract

THE recently observed rise1 in radio flux from SN1987A is earlier than predicted in models of the interaction with the observed line-emitting gas2,3. The observed size of the radio source is roughly consistent with the expected position of the supernova shock wave, which is inside the optically emitting ring. The size is also consistent with the position of the termination shock of the blue supergiant progenitor wind, and the radio increase is attributed to the interaction of the supernova shock with this density jump. The required efficiency of electron acceleration and magnetic field amplification is larger than usually occurs in supernovae and supernova remnants. Possible reasons for the enhanced radio emission are particle acceleration by the weak reflected shock that travels through the interaction region, and the action of the Richtmyer-Meshkov instability near the initial termination-shock density jump. The action of these mechanisms is time-limited; the prediction of this model is that the radio flux should begin to decline within the next year.