GRAVITATIONAL WAVE SIGNATURES OF HYPERACCRETING COLLAPSAR DISKS

Journal Article · Mon Aug 20 00:00:00 EDT 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/755/2/84· OSTI ID:22039107

Kotake, Kei ^[1]; Takiwaki, Tomoya ^[2]; Harikae, Seiji ^[3]

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1. Division of Theoretical Astronomy, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
2. Center for Computational Astrophysics, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
3. Quants Research Department, Financial Engineering Division, Mitsubishi UFJ Morgan Stanley Securities Co., Ltd., Marunouchi Bldg., 2-4-1 Marunouchi, Chiyoda-ku, Tokyo 100-6317 (Japan)

By performing two-dimensional special relativistic (SR) magnetohydrodynamic simulations, we study possible signatures of gravitational waves (GWs) in the context of the collapsar model for long-duration gamma-ray bursts. In our SR simulations, the central black hole is treated as an absorbing boundary. By doing so, we focus on the GWs generated by asphericities in neutrino emission and matter motions in the vicinity of the hyperaccreting disks. We compute nine models by adding initial angular momenta and magnetic fields parametrically to a precollapse core of a 35 M{sub Sun} progenitor star. As for the microphysics, a realistic equation of state is employed and the neutrino cooling is taken into account via a multi-flavor neutrino leakage scheme. To accurately estimate GWs produced by anisotropic neutrino emission, we perform a ray-tracing analysis in general relativity by a post-processing procedure. By employing a stress formula that includes contributions from both magnetic fields and SR corrections, we also study the effects of magnetic fields on the gravitational waveforms. We find that the GW amplitudes from anisotropic neutrino emission show a monotonic increase with time, whose amplitudes are much larger than those from matter motions of the accreting material. We show that the increasing trend of the neutrino GWs stems from the excess of neutrino emission in the direction near parallel to the spin axis illuminated from the hyperaccreting disks. We point out that a recently proposed future space-based interferometer like Fabry-Perot-type DECIGO would permit the detection of these GW signals within Almost-Equal-To 100 Mpc.

• OSTI ID: 22039107
• Journal Information: Astrophysical Journal, Vol. 755, Issue 2; 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
ASTROPHYSICS
BLACK HOLES
COMPUTERIZED SIMULATION
CORRECTIONS
COSMIC GAMMA BURSTS
COSMIC NEUTRINOS
DETECTION
EMISSION
EQUATIONS OF STATE
FLAVOR MODEL
GENERAL RELATIVITY THEORY
GRAVITATIONAL WAVES
MAGNETIC FIELDS
RADIANT HEAT TRANSFER
RELATIVISTIC RANGE
SPIN
SUPERNOVAE
TWO-DIMENSIONAL CALCULATIONS
WAVE FORMS