Finite temperature and charge fraction equation of state for numerical relativity with nuclear physics constraints*

Numerical relativity simulations of neutron star mergers require information about the finite temperature equation of state (EoS) of nuclear matter for a wide range of densities and charge fractions. We developed a new method to generate a 3 dimensional (3D) EoS given a 1D EoS that could be extracted from neutron star observations at zero temperature and beta-equilibrium. This framework relies on theoretical considerations from heavy-ion collisions and experimental constraints on symmetric nuclear matter at nuclear densities in addition to neutron star observations. Our method can precisely reproduce known microphysical EoS at any charge fraction, temperatures up to ~100 MeV, and densities up to several times nuclear saturation density and it ensures that the EoS is thermodynamically consistent and causal. The resulting code package will be publicly released in a format well-suited to numerical relativity simulations of neutron star mergers.