BLACK HOLE-NEUTRON STAR MERGERS WITH A HOT NUCLEAR EQUATION OF STATE: OUTFLOW AND NEUTRINO-COOLED DISK FOR A LOW-MASS, HIGH-SPIN CASE

Journal Article · Thu Oct 10 00:00:00 EDT 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/776/1/47· OSTI ID:22270731

Deaton, M. Brett; Duez, Matthew D. ^[1]; Foucart, Francois; O'Connor, Evan ^[2]; Ott, Christian D.; Scheel, Mark A.; Szilagyi, Bela ^[3]; Kidder, Lawrence E.

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1. Department of Physics and Astronomy, Washington State University, Pullman, WA 99164 (United States)
2. Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, Ontario M5S 3H8 (Canada)
3. TAPIR, MC 350-17, California Institute of Technology, Pasadena, CA 91125 (United States)

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 (EOS) 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{sub ☉} neutron star, 5.6 M{sub ☉} black hole), high-spin (black hole J/M {sup 2} = 0.9) system with the K{sub 0} = 220 MeV Lattimer-Swesty EOS. We find that about 0.08 M{sub ☉} of nuclear matter is ejected from the system, while another 0.3 M{sub ☉} forms a hot, compact accretion disk. The primary effects of the escaping neutrinos are (1) to make the disk much denser and more compact, (2) to cause the average electron fraction Y{sub e} of the disk to rise to about 0.2 and then gradually decrease again, and (3) to gradually cool the disk. The disk is initially hot (T ∼ 6 MeV) and luminous in neutrinos (L{sub ν} ∼ 10{sup 54} erg s{sup –1}), but the neutrino luminosity decreases by an order of magnitude over 50 ms of post-merger evolution.

• OSTI ID: 22270731
• Journal Information: Astrophysical Journal, Vol. 776, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ACCRETION DISKS
ASTRONOMY
ASTROPHYSICS
BLACK HOLES
COSMIC GAMMA BURSTS
ELECTRONS
EQUATIONS OF STATE
GENERAL RELATIVITY THEORY
LUMINOSITY
MASS
MEV RANGE
NEUTRINOS
NEUTRON STARS
NUCLEAR MATTER
POTENTIALS
SPIN
STAR ACCRETION