Heavy sterile neutrinos in stellar core-collapse

摘要

We perform spherically symmetric simulations of the core collapse of a single progenitor star of zero age main sequence mass M_(ZAMS) = 15 M_⊙ with two models of heavy sterile neutrinos in the mass range of 100 MeV/c~2. According to both models, these hypothetical particles are copiously produced in the center, stream outwards and 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 nonexploding 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, similar 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.