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Black Hole-Neutron Star Mergers with a Hot Nuclear Equation of State: Outflow and Neutrino-Cooled Disk for a Low-Mass, High-Spin Case

Authors :
Béla Szilágyi
Curran D. Muhlberger
Christian D. Ott
Francois Foucart
Evan O'Connor
Mark A. Scheel
M. Brett Deaton
Lawrence E. Kidder
Matthew D. Duez
Publication Year :
2013

Abstract

Neutrino emission significantly affects the evolution of the accretion tori formed in black hole-neutron star mergers. It removes energy from the disk, alters its composition, and provides a potential power source for a gamma-ray burst. To study these effects, simulations in general relativity with a hot microphysical equation of state and neutrino feedback are needed. We present the first such simulation, using a neutrino leakage scheme for cooling to capture the most essential effects and considering a moderate mass (1.4 M_{\odot} neutron star, 5.6 M_{\odot} black hole), high spin (black hole J/M^2=0.9) system with the K_0=220 MeV Lattimer-Swesty equation of state. We find that about 0.08 M_{\odot} of nuclear matter is ejected from the system, while another 0.3 M_{\odot} forms a hot, compact accretion disk. The primary effects of the escaping neutrinos are (i) to make the disk much denser and more compact, (ii) to cause the average electron fraction Y_e of the disk to rise to about 0.2 and then gradually decrease again, and (iii) to gradually cool the disk. The disk is initially hot (T~6 MeV) and luminous in neutrinos (L_{\nu}~10^{54} erg s^{-1}), but the neutrino luminosity decreases by an order of magnitude over 50 ms of post-merger evolution.<br />Comment: Included erratum to the end of the article: affected average neutrino energy estimates

Details

Language :
English
Database :
OpenAIRE
Accession number :
edsair.doi.dedup.....009b036cbd6630df25af5fa025b4b4e0