Neutrino Signal from Compact Objects During Their Formation, Their Mergers, or As a Signature of Electric-Charge Phase Transition

We study neutrino creation, propagation, and oscillations within an extremely magnetized background of finite-temperature nuclear matter and strange-quark matter (SQM). We focus on three particularly interesting cases and identify the astrophysical scenarios where such a signal may be found. The first case involves nuclear matter with electrons, and it is found during the central-engine stage of, both, short and long gamma-ray bursts (GRBs). Thus, for the short GRB case, it will also be associated with gravitational-wave events where there exist electromagnetic counterparts (e.g., GW170817). The second and third scenarios involve the presence of SQM. Accordingly, the second scenario occurs if SQM can become negatively charged (SQM−; which may only occur at high pressure) and, thus, it is embedded in a positron plasma. The third case may be found at the interphase where SQM transitions from positive (SQM+) to negative; here, positrons and electrons may constantly annihilate and give a distinctive neutrino signal. Therefore, this may also be a signature of the existence of strange stars. Given the wide range of magnetic fields we find in the literature, we also briefly discuss the maximum limit that a stellar-mass compact object may possess.