Long-term evolution of massive star explosions

TL;DR

This paper presents detailed simulations of core-collapse supernovae, analyzing their long-term evolution, neutrino spectra changes, and the potential for flavor oscillations affecting nucleosynthesis.

Contribution

It provides the first detailed analysis of supernova evolution up to 20 seconds post-explosion, including neutrino spectra and flavor oscillation possibilities during late stages.

Findings

Neutrino fluxes and energies decrease over time.

Spectra of all neutrino flavors become similar.

Suppression of collective flavor oscillations during early post-bounce phase.

Abstract

We examine simulations of core-collapse supernovae in spherical symmetry. Our model is based on general relativistic radiation hydrodynamics with three-flavor Boltzmann neutrino transport. We discuss the different supernova phases, including the long-term evolution up to 20 seconds after the onset of explosion during which the neutrino fluxes and mean energies decrease continuously. In addition, the spectra of all flavors become increasingly similar, indicating the change from charged- to neutral-current dominance. Furthermore, it has been shown recently by several groups independently, based on sophisticated supernova models, that collective neutrino flavor oscillations are suppressed during the early mass-accretion dominated post-bounce evolution. Here we focus on the possibility of collective flavor flips between electron and non-electron flavors during the later, on the order of seconds, evolution after the onset of an explosion with possible application for the nucleosynthesis of heavy elements.