Interpreting Gravitational Waves and Developing Relativistic Multiphysics Solvers for Core-collapse Supernova Simulations

Core-collapse supernovae (CCSNe) mark the endpoint for millions of years of massive stellar evolution. After a successful explosion, supernovae increase the metallicity of the interstellar medium, generate intense electromagnetic radiation ionizing their surroundings, generate compact objects such as black holes or neutron stars, and create ripples in spacetime---gravitational waves (GWs). Advances in supernova theory over the past few decades have furthered our understanding of CCSNe. However, constraints on the physics enshrouded in the supernova center would further illuminate their explosion mechanisms. Advances in high performance computing (HPC) resources and the ever-increasing sensitivities of GW observatories have positioned the field of astrophysics between two recent technological advances. The work presented here leverages HPC to perform CCSN simulations, allowing astronomers to translate between GW signals and internal physics. Using this insight, astronomers are better positioned to constrain the physics driving these explosive events that have such a widespread influence throughout astronomy.Investigating the evolution of 12-, 20-, 40-, and 60 solar mass progenitors, I perform axisymmetric neutrino radiation-hydrodynamic CCSN simulations, to relate the convective activity behind the supernova shock to the expected GW strength. I quantify how the rotational content of the supernova lowers GW frequencies. I present a novel method that combines two features of a single GW event to constrain the mass distribution within the stellar progenitor. By only requiring the two most detectable parts of the GW signal, astronomers can also potentially predict the explosion properties ~days before shock breakout. I present work with my undergraduate research assistant, that considers the impact of viewing angle on detecting GWs from CCSNe. Presented is a novel analysis method to identify the distribution of GW emission over all angles, accompanied with results showing that the preferred direction of GW emission for CCSNe migrates over time. Lastly, I present new numerical solvers targeted at exascale computing platforms that account for magnetized fluid evolution with velocities near the speed of light and in extreme spacetimes. These solvers are accompanied with stringent baseline tests, paired with 1D and 2D supernova simulations making use of these features.