The importance of neutrino opacities for the accretion luminosity in spherically symmetric supernova models

Based on general relativistic three-flavor Boltzmann neutrino transport, we compare simulations of the postbounce evolution for five different stellar progenitors with 13 and 20 solar masses (Nomoto & Hashimoto '88), and 15, 25, and 40 solar masses (Woosley & Weaver '95).