TYPE-II SUPERNOVAE AND BOLTZMANN NEUTRINO TRANSPORT - THE INFALL PHASE

We present the results from a computer simulation of the gravitational collapse of a 1.17 M. iron core extracted from a Nomoto-Hashimoto 13 M. presupernova star. The results are obtained with a Newtonian gravity, O(v/c) Lagrangian hydrodynamics code coupled to an O(v/c) Boltzmann solver for the neutrino transport. We include electron capture on nuclei and free protons and electron neutrino absorption on nuclei and free neutrons. We also include conservative scattering of electron neutrinos on free protons and neutrons and conservative coherent scattering of electron-neutrinos on nuclei. We use the Baron-Cooperstein equation of state. Our results are presented together with the results from a simulation carried out with Bruenn's radiation hydrodynamics code for the same initial model and equation of state. Bruenn's code uses a multigroup flux-limited diffusion approximation for the neutrino transport.