Supernova remnants - A generalized theoretical approach to the radio evolution

The observational statistics for more than 100 SNRs is used to investigate the predictions of various models for SNR radio emission. In one model which fits the data, the magnetic field stays constant and the average energy of an electron decays as D exp-1. The compressed interstellar magnetic field could provide the required field, a possibility outlined by van der Laan (1962) to account for a few SNRs of intermediate age. It is suggested that this model may be appropriate over most of the lifetime of a typical SNR.