Analysis of Supernova Spectra David J. Jeffery and David Branch

A simple and fast analysis procedure for supernova spectra is presented. Included in the presentation is an introduction to the Sobolev method of radiative transfer, a description of a simple model of a supernova, a catalogue of line profiles illustrating line formation in the simple supernova model, and an example analysis of the SN 1987A photometry and optical spectra. The SN 1987A analysis is intended as a benchmark to which more advanced and detailed analyses can be compared. Synthetic spectra calculated in the SN 1987A analysis using solar-composition thermodynamic-equilibrium predicted line optical depths are in rough qualitative agreement with the observed spectra; the agreement becomes poorer after day 100 after the explosion. It is probable that for the period from day 16 to about day 100 after the explosion that the SAAO photometric radius is close to being the true photospheric radius: earlier than day 16 the photometric radius is too small.