Black hole-neutron star mergers using a survey of finite-temperature equations of state

• Published in: arXiv.org
• Main Authors: Wyatt Brege, Duez, Matthew D, Foucart, Francois, Deaton, M Brett, Caro, Jesus, Hemberger, Daniel A, Kidder, Lawrence E, O'Connor, Evan, Pfeiffer, Harald P, Scheel, Mark A
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 25.04.2018
• Subjects: Accretion disks; Black holes; Computer simulation; Disruption; Ejecta; Equations of state; Gamma rays; Gravitational effects; Gravitational waves; Inflow; Mathematical models; Neutrinos; Neutron stars; Neutrons; Nuclear models; Nuclear physics; Physics - General Relativity and Quantum Cosmology; Physics - High Energy Astrophysical Phenomena; Star mergers; Stellar evolution; Stiffness; Temperature dependence
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1804.09823

Each of the potential signals from a black hole-neutron star merger should contain an imprint of the neutron star equation of state: gravitational waves via its effect on tidal disruption, the kilonova via its effect on the ejecta, and the gamma ray burst via its effect on the remnant disk. These effects have been studied by numerical simulations and quantified by semi-analytic formulae. However, most of the simulations on which these formulae are based use equations of state without finite temperature and composition-dependent nuclear physics. In this paper, we simulate black hole-neutron star mergers varying both the neutron star mass and the equation of state, using three finite-temperature nuclear models of varying stiffness. Our simulations largely vindicate formulae for ejecta properties but do not find the expected dependence of disk mass on neutron star compaction. We track the early evolution of the accretion disk, largely driven by shocking and fallback inflow, and do find notable equation of state effects on the structure of this early-time, neutrino-bright disk.