The prompt-shock supernova mechanism. I - The effect of the free-proton mass fraction and the neutrino transport algorithm

Results are presented of an extensive numerical investigation of the prompt-shock supernova mechanism. This paper focuses on the effect of the free-proton mass fraction Xp given by the equation of state (EOS) and of the various levels of standard neutrino physics on the success of the bounce shock in producing a supernova-like explosion in a prompt manner. When neutrino-electron scattering (NES) is turned off and only e-type neutrinos are transported, vigorous explosions are produced for a wide range of values for Xp. The inclusion of NES considerably restricts the possible values of Xp for successful explosions. The additional inclusion of all neutrino flavors further restricts the possible values of Xp. Successful shocks can still be produced (depending on how the shock energy is defined), but only for very small values of Xp.