Simulations of Core Collapse Supernovae in One and Two Dimensions Using Multigroup Neutrino Transport

Current supernova modeling revolves around the idea that the stalled supernova shock is reenergized by absorption of electron neutrinos and antineutrinos on the shock-liberated nucleons behind it. Key to this process is the neutrino transport in the critical semitransparent region encompassing the neutrinospheres. Potentially aiding this process is convection below the neutrinospheres and the shock, although the verdict has been mixed. In semitransparent regions, neutrino transport approximations such as multigroup flux-limited diffusion (MGFLD) break down. Moreover, neutrino shock reheating/revival depends sensitively on the emergent neutrinosphere luminosities and spectra, and on the neutrino inverse flux factors between the neutrinospheres and the shock. At the very least, computation of these quantities by approximate transport methods have to be checked against exact methods, i.e., against Boltzmann neutrino transport. We present results from oneand two-dimensional supernova simulations. In one dimension, beginning from postbounce slices obtained from Bruenn’s MGFLD simulations, which are subsequently thermally and hydrodynamically frozen, we compute stationary state neutrino distributions with MGFLD and Boltzmann neutrino transport. From these, we compute and compare the neutrino luminosities, RMS energies, and inverse flux factors, and the net neutrino heating rate, between the neutrinospheres and the shock. In two dimensions, beginning with the same postbounce profiles, we couple one-dimensional MGFLD to two-dimensional PPM hydrodynamics to investigate “prompt” convection below the neutrinospheres and “neutrino-driven” convection below the shock. At the expense of dimensionality, we implement neutrino transport that is multigroup and that computes with sufficient realism transport through