Supernova neutrinos: The accretion disk scenario

Abstract

Neutrinos from core collapse supernovae can be emitted from a rapidly accreting disk surrounding a black hole, instead of the canonical protoneutron star. For galactic events, detector count rates are considerable and in fact can be in the thousands for Super-Kamiokande. The rate of occurrence of these accreting disks in the Galaxy is predicted to be on the order of $\sim {10}^{-5}{\mathrm{yr}}^{-1}$, yet there is little observational evidence to provide an upper limit on their formation rate. It would therefore be useful to discriminate between neutrinos which have been produced in a protoneutron star and those which have been produced accretion disks. In order to distinguish between the two scenarios, either the time profile of the neutrino luminosity, total energetics, or the relative fluxes of different neutrino flavors may be considered. The flavor content would clearly point to one scenario or the other.