Radio Supernovae

The observation, calibration and analysis of extensive new results on radio supernovae (RSNs) are discussed, while presenting most other available data and discussing their accuracy and applicability; the combined data set is then used to investigate the class properties of RSNs, deriving descriptive parameters for their light curves' gross features that are applied to several models of the phenomenon in order to investigate their relative merits and relations to the various types and subtypes of supernovae. All RSNs are found to turn on very sharply in the radio regime, with the turn on occurring first at shorter wavelengths and slowly progressing to longer ones with time. This appears to be explainable by a change of optical depth in external thermal free-free absorption. After the initially sharp turn-on, a differentiation among supernova types occurs.