X-Ray and gamma-Rays from a Non-Spherical Patchy Supernova Ejecta

The Japanese X-ray astronomy satellite Ginga observed X-rays from the region of SN1987A. In many model calculations, the hard component of the X-rays has been interpreted by the Compton degradation of line gamma-rays from the decay of (56) Co. In such calculations is assumed a spherically symmetric supernova explosion in which Ansatz of convection is introduced. A three dimensional numerical simulation recently performed by Nagasawa et al. shows, without the Ansatz of convection, that the supernova explosion is non-spherical and the shell becomes highly patchy. Since the formation of such patchy structure of the supernova shell seems very probable, we computed the light curve and the spectrum of hard X-rays and gamma-rays using such a patchy supernova shell by the Monte Carlo Method and compared our results with those by the spherical shell. Our results are not much different from the spherical shell case, at least, for the hard spectrum. The behavior of the line gamma-rays largely depends on the structure of the shell just on the line of sight, and there is a possibility that the very early emergence of the line gamma-rays is due to the patchy structure rather than too much of (56) Co mixing to the outer layer of the shell.