Explodability of Core-Collapse Supernovae: Roles of Neutrino-Driven Convection, the Nuclear Equation of State, and the Progenitor Structure

Core-collapse supernovae are one of the most complex astrophysical environments where nuclear physics, general relativity, particle physics, and magneto-hydrodynamics combine in a highly non-linear fashion to produce some of the most spectacular events in the Universe. Extremely complex and computationally expensive multi-dimensional simulations are required to properly account for all the details and nuances of the physics of supernovae. In this thesis, I have taken a different approach and used a simplified, spherically symmetric model that I modified with relativistic time-dependent mixing-length theory. This model was calibrated to reproduce the same results as multi-dimensional simulations but is computationally very cheap and could be used for parameter studies that are impossible in two and three-dimensions.

I illustrated the general relativistic mixing-length theory model that I used and analyze the differences with more approximate Newtonian simulations. Small but significant discrepancies can be observed, a sign that future multi-dimensional simulations should account for general relativistic effects, instead of using approximate multipole expansions as it is currently most common.

I have shown how I used this code to analyze the effect of the nuclear equation of state on the explosion. From simulations with several equations of state, a clear correlation can be found between the entropy at the star's center in the first $\sim 10$ ms after bounce and the strength of the subsequent explosion. This is a general trend seen in different progenitors and across all of the equations of state considered. A comparison with previous studies that considered only a subset of these EOSs was also performed.

Finally, I have illustrated the criterion I developed to predict the outcome of the explosion solely based on the pre-supernova thermodynamic profiles. This criterion was validated using several hundreds of simulations, and compared to a recent and parallel study that confirms its robustness. I have also provided a detailed comparison with previous studies that predict a different explodability. There, I have shown how the inclusion in our models of neutrino-driven convection, a crucial physical mechanism for the explosion, accounts for this difference.