B. Sykes | Searcharxiv

arXiv2026

Core-collapse supernovae and supernova neutrinos

Core-collapse supernovae are the terminal explosions of massive stars. After successive phases of nuclear fusion proceeding up to silicon burning, these stars form an iron core that is supported by electron degeneracy pressure. The core eventually collapses to a proto-neutron star, and in most cases the outer layers of the star are ejected by a shock wave, with a kinetic energy of order $10^{51}\,\mathrm{erg}$. Neutrinos and multi-dimensional fluid flow play a key role in extracting energy from the collapsed core to drive the explosion. After adumbrating the astrophysical context of stellar evolution and transient observations, this chapter sketches the modern theory of neutrino-driven supernova explosions, and discusses the key role of nuclear physics and neutrino interaction rates in the supernova problem. It also outlines the role of neutrinos and gravitational waves as probes into the supernova core.

astro-ph.HE↗

arXiv2022

A Black-Hole Excision Scheme for General Relativistic Core-Collapse Supernova Simulations

Fallback supernovae and the collapsar scenario for long-gamma ray burst and hypernovae have received considerable interest as pathways to black-hole formation and extreme transient events. Consistent simulations of these scenarios require a general relativistic treatment and need to deal appropriately with the formation of a singularity. Free evolution schemes for the Einstein equations can handle the formation of black holes by means of excision or puncture schemes. However, in constrained schemes, which offer distinct advantages in long-term numerical stability in stellar collapse simulations over well above $10^{4}$ light-crossing time scales, the dynamical treatment of black-hole spacetimes is more challenging. Building on previous work on excision in conformally flat spacetimes, we here present the implementation of a black-hole excision scheme for supernova simulations with the CoCoNuT-FMT neutrino transport code. We describe in detail a choice of boundary conditions that ensures long-time numerical stability, and also address upgrades to the hydrodynamics solver that are required to stably evolve the relativistic accretion flow onto the black hole. The scheme is currently limited to a spherically symmetric metric, but the hydrodynamics can be treated multi-dimensionally. For demonstration, we present a spherically symmetric simulation of black-hole formation in an $85 M_\odot$ star, as well as a two-dimensional simulation of the fallback explosion of the same progenitor. These extend past 9s and 0.3s after black-hole formation, respectively.

astro-ph.HE↗