We study out-of-thermodynamic equilibrium effects in neutron star mergers with 3D general-relativistic neutrino-radiation large-eddy simulations. During merger, the cores of the neutron stars remain cold (T∼ a few MeV) and out of thermodynamic equilibrium with trapped neutrinos originating from the hot collisional interface between the stars. However, within ∼2−3 milliseconds matter and neutrinos reach equilibrium everywhere in the remnant. Our results show that dissipative effects, such as bulk viscosity, if present, are only active for a short window of time after the merger.
@article{arxiv.2311.00031,
title = {Neutrino trapping and out-of-equilibrium effects in binary neutron star merger remnants},
author = {Pedro Luis Espino and Peter Hammond and David Radice and Sebastiano Bernuzzi and Rossella Gamba and Francesco Zappa and Luis Felipe Longo Micchi and Albino Perego},
journal= {arXiv preprint arXiv:2311.00031},
year = {2023}
}