Speaker
Description
The gravitational collapse of massive stars at the end of their life leads to powerful supernova explosions that produce new stellar-sized compact objects, regulate the dynamics of their host galaxies, and produce new heavy elements that contribute to the cosmic chemical evolution. In presence of fast rotation and strong magnetic fields, such explosions reach extremely high energies that can explain sources such as hypernovae and long gamma-ray bursts, which are the most violent transients observable in the Universe. The goal of our work is to produce state-of-the-art axisymmetric models of magnetorotational explosions rely on nuclear equations of state (EoS) whose microphysical uncertainties remain one of the dominant sources of variability in the predicted dynamics. In particular, differences in the stiffness, composition, and finite-temperature behavior of the EoS can significantly affect the collapse, bounce, and jet-launching phases, even when employing advanced relativistic magnetohydrodynamic (RMHD) treatments, neutrino-matter interactions, and general-relativistic corrections. In particular, we aim to quantify the impact of the chosen EoS for dense matter on the explosion dynamics and the resulting multi-messenger emission, including neutrinos and gravitational waves.
We use the Aenus-Alcar RMHD code to perform simulations for different EoS. Each simulation starts from the same initial condition, using a standard pre-supernova model with solar metallicity and a zero-age main sequence mass of 20 solar masses, endowed with a dipolar magnetic field configuration. Variations in the stiffness, nuclear interactions, and treatment of nuclei among the different EoS lead to significant differences in the explosion dynamics, particularly in the bounce time, moment of inertia, explosion energy, and mass of the ejected material.
In addition, we test different numbers of energy bins in the spectral neutrino-transport scheme to assess the sensitivity of neutrino heating and emission to the energy resolution. We also investigate the impact of different pseudo-Newtonian gravity treatments, evaluating how alternative approximations to the gravitational potential influence collapse dynamics, shock propagation, and jet formation. These additional tests provide a more complete picture of the numerical and physical uncertainties affecting magnetorotational supernova models.