Nir Sapir will talk about SN shock breakout.
Abstract:
Supernovae are classified into different types according to the characteristics of the observed light curve and
spectra. However, the connection between specific progenitors and some supernovae types is still an open issue.
The early light curve, when the shock produced by the explosion breaks out of the star, has been suggested to give
information regarding stellar parameters such as the progenitor's radius. The problem of a non-relativistic
radiation mediated shock breaking out from a stellar envelope will be discussed, and detailed spectral
calculations will be presented. Unlike previous studies, the effect of Compton scattering on the radiation
spectrum is included here in the radiation-hydrodynamics calculations, in the form of the Kompaneets equation.
These calculations confirm previously assumed Compton equilibrium between matter and radiation, and show again
that there is a signature spectral shape for the emission following shock breakout. This allows the inference of
both the progenitor's radius and the shock velocity from the fluence spectrum and the total emitted energy.
Problems that remain with the shock breakout model regarding the incompatibility with observed X-ray flashes and
missing X-ray flashes will also be discussed.