Effect of Neutrino Flavor Conversions in Core-Collapse Supernova Simulations

Jakob Ehring^1*

¹物理研究所, 中央研究院, 臺北市, Taiwan

* Presenter:Jakob Ehring, email:ehring@as.edu.tw

Core-collapse supernovae are extremely energetic explosions and the transition of the life of massive stars to compact remnant objects (neutron stars or black holes). Gravitational potential energy is converted to kinetic energy during the collapse and converted to internal energy as the infall comes to a sudden stop when densities reach nuclear saturation density. In the dense environment only weakly interacting neutrinos can escape. Their emission is the main driver for the cooling of the compact remnant. At the same time their number is high enough that the remaining interaction with the surrounding material heats stellar matter and drives the explosion.
Over the last decade it has become clear that the sheer number of neutrinos produced also enables efficient flavor conversions as a consequence of coherence built up in forward scattering of neutrinos on neutrinos. The dynamics have no analytical solution and the relevant scales are much smaller than any achievable resolution in numerical simulations. This constitutes a major uncertainty of numerical modeling of core-collapse supernovae.
I show the results of simulations that make use of a sub-grid model of neutrino flavor conversions. This allows me to gauge to what extent neutrino flavor conversions change the outcome of numerical simulations. I show that the effect is indeed non-linear and does not only modify certain aspects. Under certain conditions, it can turn black hole formation into a successful explosion and even the other way round.

Keywords: Core-Collapse Supernovae, Neutrinos, Numerical Simulations, Collective Osciallations