TRAVEL-TIME DELAYS IN RADIO SUPERNOVA REMNANT 1987A

In the early stages of evolution of supernovae, the shock front expand s at a significant fraction of the speed of light. Effects due to the finite speed of propagation of the radio emission may therefore be imp ortant, We discuss the inclusion of travel-time delays in one particul ar model for the radio emission from SNR 1987A. We consider a spherica lly symmetric geometry and a time-dependent treatment of diffusive ele ctron acceleration at the expanding shock, Analytic expressions for th e flux density are presented, and we show that propagation delays are important at the initial switch-on of the emission, but not for its lo ng-term evolution.