Emergence of hyperons in failed supernovae: trigger of the black hole formation

TL;DR

This study uses relativistic simulations to show that hyperons appear during massive star collapse, influencing black hole formation and neutrino signals, which could serve as observational probes.

Contribution

It demonstrates the role of hyperons in black hole formation from failed supernovae using a new hyperonic EOS in dynamical simulations.

Findings

Hyperons appear 0.5-0.7 seconds after bounce, triggering re-collapse.

Neutrino emission stops earlier with hyperons than with nucleonic matter.

Neutrino energies and luminosities are similar regardless of hyperon presence.

Abstract

We investigate the emergence of strange baryons in the dynamical collapse of a non-rotating massive star to a black hole by the neutrino-radiation hydrodynamical simulations in general relativity. By following the dynamical formation and collapse of nascent proto-neutron star from the gravitational collapse of a 40Msun star adopting a new hyperonic EOS table, we show that the hyperons do not appear at the core bounce but populate quickly at ~0.5-0.7 s after the bounce to trigger the re-collapse to a black hole. They start to show up off center owing to high temperatures and later prevail at center when the central density becomes high enough. The neutrino emission from the accreting proto-neutron star with the hyperonic EOS stops much earlier than the corresponding case with a nucleonic EOS while the average energies and luminosities are quite similar between them. These features of neutrino signal are a potential probe of the emergence of new degrees of freedom inside the black hole forming collapse.