Core Collapse Supernova Gravitational Waves: Theory, Detection, and Parameter Estimation

This dissertation aims to advance the understanding of gravitational wave (GW) production in neutrino-driven core collapse supernovae (CCSNe) by providing a comprehensive analysis of the GW signals from state-of-the-art CCSN simulations. It further advances our understanding of GW production in CCSNe by investigating the effects of differing nuclear equations of state (EOS) and stellar structures on GW signals. CCSNe are explosions of massive stars initiated by gravitational collapse of their inner cores. This explosion is generated by the release of gravitational binding energy as the core transitions to a proto-neutron star (PNS) that evolves into either a neutron star or black hole over the course of tens of seconds. The PNS evolution produces the dominant contribution to the high frequency GW signal emitted by CCSNe. Thus, GWs provide a unique window directly into the deepest regions of the CCSN, otherwise opaque to electromagnetic emissions. The analysis conducted in this dissertation utilizes three-dimensional CCSN simulations from the state-of-the-art CHIMERA code and combines a regional decomposition of GW emission with a modal analysis of the PNS. The regional decomposition provides insight into source of GW emission, and the modal analysis connects that insight to the quasi-normal oscillation modes of the PNS that produce those GWs. Both analyses show that the gravitational wave emission begins near the surface of the PNS but is eventually dominated by emission deep within the PNS. The regional decomposition indicates that the initial PNS surface dominated GW emission is excited from matter accretion onto the PNS, and the later deep interior PNS dominated GW emission is excited by Ledoux convection and convective overshoot. The modal analysis confirms that the character of quasi-normal modes of oscillation of the PNS changes precisely at the same time the source of emission changes, initially described by buoyancy-driven oscillations and later by pressure-driven oscillations. Using two-dimensional CHIMERA simulations, this dissertation demonstrates that the high frequency component of CCSNe GW signals is sensitive to the nuclear EOS, and, in principle, these EOS effects are detectable in current generation GW detectors. Finally, this dissertation shows the effects of progenitor stellar structure on CCSN GW emission.

This dissertation contains edited text and results from published journal articles

Mezzacappa et al. (2023); Murphy et al. (2024, 2025b) and a soon to be published

article Murphy et al. (2025a), reproduced with permission from the publisher.