# Equation of state effects in the core collapse of a $20$-$M_\odot$ star

## TL;DR

This study explores how uncertainties in dense matter equations of state influence core-collapse supernovae and neutron star properties, highlighting the critical role of nucleon effective mass in supernova dynamics and neutrino signals.

## Contribution

We constructed 97 new finite-temperature EOSs consistent with current constraints and systematically analyzed their impact on supernova and neutron star outcomes.

## Key findings

- Nucleon effective mass at high densities is the main uncertainty affecting neutrino signals.
- Higher effective mass at nuclear saturation density increases the likelihood of supernova explosion.
- Changes in other EOS parameters mainly influence cold neutron star properties, not supernova dynamics.

## Abstract

Uncertainties in our knowledge of the properties of dense matter near and above nuclear saturation density are among the main sources of variations in multi-messenger signatures predicted for core-collapse supernovae (CCSNe) and the properties of neutron stars (NSs). We construct 97 new finite-temperature equations of state (EOSs) of dense matter that obey current experimental, observational, and theoretical constraints and discuss how systematic variations in the EOS parameters affect the properties of cold nonrotating NSs and the core collapse of a $20\,M_\odot$ progenitor star. The core collapse of the $20\,M_\odot$ progenitor star is simulated in spherical symmetry using the general-relativistic radiation-hydrodynamics code GR1D where neutrino interactions are computed for each EOS using the NuLib library. We conclude that the effective mass of nucleons at densities above nuclear saturation density is the largest source of uncertainty in the CCSN neutrino signal and dynamics even though it plays a subdominant role in most properties of cold NS matter. Meanwhile, changes in other observables affect the properties of cold NSs, while having little effect in CCSNe. To strengthen our conclusions, we perform six octant three-dimensional CCSN simulations varying the effective mass of nucleons at nuclear saturation density. We conclude that neutrino heating and, thus, the likelihood of explosion is significantly increased for EOSs where the effective mass of nucleons at nuclear saturation density is large.