Topics in the theory of core-collapse supernovae

Abstract

We study the physics of core-collapse supernovae and the neutron stars they create. We study the microphysics of neutrino interactions and demonstrate the importance of two processes previously ignored in full supernova simulations: inelastic neutrino-nucleon scattering and nucleon-nucleon bremsstrahlung. We show that these processes dominate neutrino-electron scattering and electron-positron annihilation as thermalization and production mechanisms, respectively, for mu- and tau-neutrinos in regimes vital to emergent spectrum formation. In addition, we solve the general-relativistic steady-state eigenvalue problem of neutrino-driven protoneutron star winds, which immediately follow core-collapse supernova explosions. We provide velocity, density, temperature, and composition profiles and explore the systematics and structures generic to such a wind for a variety of protoneutron star characteristics. Furthermore, we derive the entropy, dynamical timescale, and compositions essential in assessing this site as a candidate for r-process nucleosynthesis. Finally, we construct dynamical models of core-collapse supernovae. We employ a full solution to the transport equation for each neutrino species, a realistic high-density nuclear equation of state, and explicit hydrodynamics. We present results from a set of different supernova progenitors. We vary the microphysics and nuclear equation of state and compare our results to those of other groups. We examine the electron-neutrino breakout phenomenon and address the importance of nucleon-nucleon bremsstrahlung and inelastic neutrino-electron scattering in mu and tau neutrino spectrum formation. We convolve the emergent spectra obtained in these models with terrestrial neutrino detectors and find that the electron-neutrino breakout burst can likely be observed and identified uniquely.