Heavy sterile neutrinos in stellar core-collapse

TL;DR

This study explores how hypothetical heavy sterile neutrinos could influence supernova explosions, potentially leading to new explosion mechanisms and observable signals, by simulating their production, decay, and energy transfer in stellar core-collapse.

Contribution

It introduces the first spherically symmetric simulations of core-collapse supernovae incorporating heavy sterile neutrinos, revealing their potential to cause successful explosions and unique observational signatures.

Findings

Sterile neutrinos can induce successful supernova explosions.

Explosion energies can be very high depending on neutrino parameters.

The resulting electromagnetic signals may differ significantly from typical supernovae.

Abstract

We perform spherically symmetric simulations of the core collapse of a single progenitor star of zero age main sequence mass $M_{\rm ZAMS} = 15 \, M_{\odot}$ with two models of heavy sterile neutrinos in the mass range of hundred MeV$/c^2$. According to both models, these hypothetical particles are copiously produced in the center, stream outwards a subsequently decay releasing energy into final states (including neutrinos) of the Standard Model. We find that they can lead to a successful explosion in otherwise non-exploding progenitors. Depending on their unknown parameters (e.g., mass and coupling constants with matter), we obtain either no explosion or an explosion of one of two types, i.e., through heating of gas downstream of the stalled shock wave, similarly to the standard scenario for supernova explosions or through heating of gas at higher radii that ejects matter from the outer core or the envelope while the center continues to accrete matter. In both cases, the explosion energies can be very high. We presume that this new type of explosion would produce an electromagnetic signal that significantly differs from common events because of the relative absence of heavy elements in the ejecta. The combination of core-collapse simulations and astrophysical observations may further constrain the parameters of the sterile neutrinos.