The impact of nuclear equations of state on the dynamics and multi-messenger emission of magnetorotational stellar explosions

Abstract

The gravitational collapse of massive stars at the end of their life leads to powerful supernova explosions that produce compact objects, regulate the dynamics of host galaxies, and contribute to cosmic chemical evolution. In the presence of fast rotation and strong magnetic fields, such explosions can reach extreme energies, explaining sources such as hypernovae and long gamma-ray bursts. We investigate the impact of variations in the nuclear equation of state (EoS) on magnetorotational explosions and their multimessenger emission, including neutrinos and gravitational waves. Differences in stiffness, composition, and finite-temperature behavior of the EoS affect the collapse, bounce, and jet-launching phases. Using the Aenus-Alcar code, which includes relativistic magnetohydrodynamics, two-moment neutrino transport, neutrino-matter interactions, and general-relativistic corrections, we perform axisymmetric simulations with different EoSs. All models start from the same pre-supernova progenitor with solar metallicity, a zero-age main sequence mass of 20 solar masses, a dipolar magnetic field, and a shellular rotation profile. The different EoSs produce significant variations in explosion dynamics, proto-neutron star properties, ejecta mass, and multimessenger signals. Our results show that magnetorotational core-collapse supernova signatures depend not only on the cold stiffness of the EoS, but also on its thermal and compositional properties, highlighting the importance of combining gravitational-wave and neutrino observations to constrain dense matter physics and the explosion mechanism.