Finite-Temperature Effects on the Bar-Mode Instability Threshold for Realistic Proto-Neutron Stars

The dynamics of newly formed, hot proto-neutron stars (NS) are crucial for understanding the later stages of core-collapse supernovae and their potential as gravitational wave (GW) sources. Such rapidly rotating NSs may be susceptible to the bar-mode instability, producing GWs that could probe the dense-matter equation of state (EOS). Previous studies of unstable NSs, however, were limited by the use of polytropic EoSs, ignoring finite-temperature effects. Here we use the latest, Charm++ parallelized version of our general relativistic hydrodynamics code, GRoovy, to self-consistently model the dynamical bar-mode instability in full general relativity, for both initially cold and hot NSs. We constrain the instability threshold for both a soft and stiff EoS, and compare these to the values found using a polytropic EoS. This work reveals how finite-temperature effects may impact the instability threshold and the resulting GWs.