Momentum flow in black-hole binaries. II. Numerical simulations of equal-mass, head-on mergers with antiparallel spins

Journal Article · Wed Sep 15 00:00:00 EDT 2010 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.82.064031· OSTI ID:21421173

Lovelace, Geoffrey ^[1]; Yanbei, Chen; Cohen, Michael; Kaplan, Jeffrey D; Keppel, Drew; Matthews, Keith D; Nichols, David A; Scheel, Mark A; Sperhake, Ulrich ^[2]

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1. Center for Radiophysics and Space Research, Cornell University, Ithaca, New York, 14853 (United States)
2. Theoretical Astrophysics 350-17, California Institute of Technology, Pasadena, California 91125 (United States)

Research on extracting science from binary-black-hole (BBH) simulations has often adopted a 'scattering matrix' perspective: given the binary's initial parameters, what are the final hole's parameters and the emitted gravitational waveform? In contrast, we are using BBH simulations to explore the nonlinear dynamics of curved spacetime. Focusing on the head-on plunge, merger, and ringdown of a BBH with transverse, antiparallel spins, we explore numerically the momentum flow between the holes and the surrounding spacetime. We use the Landau-Lifshitz field-theory-in-flat-spacetime formulation of general relativity to define and compute the density of field energy and field momentum outside horizons and the energy and momentum contained within horizons, and we define the effective velocity of each apparent and event horizon as the ratio of its enclosed momentum to its enclosed mass-energy. We find surprisingly good agreement between the horizons' effective and coordinate velocities. During the plunge, the holes experience a frame-dragging-induced acceleration orthogonal to the plane of their spins and their infall ('downward'), and they reach downward speeds of order 1000 km/s. When the common apparent horizon forms (and when the event horizons merge and their merged neck expands), the horizon swallows upward field momentum that resided between the holes, causing the merged hole to accelerate in the opposite ('upward') direction. As the merged hole and the field energy and momentum settle down, a pulsational burst of gravitational waves is emitted, and the merged hole has a final effective velocity of about 20 km/s upward, which agrees with the recoil velocity obtained by measuring the linear momentum carried to infinity by the emitted gravitational radiation. To investigate the gauge dependence of our results, we compare generalized harmonic and Baumgarte-Shapiro-Shibata-Nakamura-moving-puncture evolutions of physically similar initial data; although the generalized harmonic and Baumgarte-Shapiro-Shibata-Nakamura-moving-puncture simulations use different gauge conditions, we find remarkably good agreement for our results in these two cases. We also compare our simulations with the post-Newtonian trajectories and near-field energy-momentum.

• OSTI ID: 21421173
• Journal Information: Physical Review. D, Particles Fields, Vol. 82, Issue 6; Other Information: DOI: 10.1103/PhysRevD.82.064031; (c) 2010 American Institute of Physics; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ACCELERATION
BINARY STARS
BLACK HOLES
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
DENSITY
GENERAL RELATIVITY THEORY
GRAVITATIONAL RADIATION
GRAVITATIONAL WAVES
LINEAR MOMENTUM
MASS
NONLINEAR PROBLEMS
SCATTERING
SPACE-TIME
SPIN
VELOCITY
WAVE FORMS
ANGULAR MOMENTUM
EVALUATION
FIELD THEORIES
PARTICLE PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
RELATIVITY THEORY
SIMULATION
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