Towards an Understanding of Core-Collapse Supernovae

Abstract

The explosion mechanism of core-collapse supernovae (CCSNe) is a long-standing astrophysical problem buttressed with over half a century of computational research. Neutrino heating of the collapsing mantle, wherein a fraction of the profuse neutrino luminosity in a collapsing star deposits energy onto the stalled shock, remains the preferred explosion mechanism for garden-variety CCSNe. Recent improvements in neutrino physics and in supercomputer power jointly ushered in new capabilities for the study of CCSNe. F{\sc{ornax}} is an optimized state-of-the-art hydrodynamics/radiative transfer code with detailed microphysics and scalable design that effectively takes advantage of these developments. I implement F{\sc{ornax}} to provide a comprehensive, multi-dimensional study of CCSNe $-$ horizontally-integrated, across a a broad suite of progenitor stars, and vertically-integrated, from explosion mechanism to observational signatures.

I provide a broad introduction of the topic, the code F{\sc{ornax}}, and the rich history of research in CCSNe in Chapter\,\ref{ch:intro}. Chapter\,\ref{ch:micro} looks at the sensitive dependence of explosion outcome on neutrino microphysics, in particular the role of many-body interactions and inelastic neutrino scattering. Chapter\,\ref{ch:2D} builds on these results to identify drivers of explosion outcome in a series of 2D axisymmetric simulations. Chapter\,\ref{ch:3D} introduces the first 3D simulation by F{\sc{ornax}}. A 16-M$_{\odot}$ progenitor is carried out to roughly one second post-bounce, exploding promptly and robustly. The results highlight the need to carry simulations out longer, to several seconds, to identify asymptotic explosion energies. In Chapter\,\ref{ch:obs}, I look at neutrino and gravitational wave observational signatures, and their correlations with core physical dynamics, with a series of 11 progenitors evolved in 3D. This is the largest suite of 3D simulations to date, allowing a study of global characteristics of a diverse set of progenitor stars. The synergistic study of neutrinos and gravitational waves in forthcoming detectors can be used to profitably study physical phenomena in the supernova core.

CCSNe study has followed a Maslow hierarchy in ambition: first, producing successful explosions; second, producing robust explosion energies, and lastly, producing CCSNe consistent with observable diagnostics. My thesis establishes well the first point, embarks on the second, and courts the third.