Black Hole-Black Hole Binary Merger in Full General Relativity

         Zachariah B. Etienne
         Yuk Tung Liu
         Stuart L. Shapiro

University of Illinois at Urbana-Champaign


The calculation of a binary black hole inspiral and coalescence is one of the great triumphs of numerical relativity. The successful solution to this problem has required contributions from many people working over many years. The chief ingredients include a stable algorithm to solve Einstein's field equations in 3+1 dimensions, valid initial data for two black holes in quasiequilibrium circular orbit, a means of avoiding the black hole spacetime singularity on the computational grid, a good gauge choice for performing the evolution, and adaptivity to achieve high resolution both in the strong-field region near the black holes and in the far zone where the gravitational waves are measured. By now, solving binary black hole coalescence on computers has become almost routine.

By simulating the gravitational radiation waveforms from black hole-black hole (BHBH) mergers, we hope to test strong-field general relativity by comparing theoretical waveform templates with measurements made by ground-based laser interferometers like LIGO (Laser Inteferometer Gravitational Wave Observatory), VIRGO, GEO, and TAMA, and space-based interferometers like LISA (Laser Interferometer Space Antenna). These numerical calculations are especially important because BHBH binaries are expected to be among the most promising sources of gravitational waves. Also, BHBH merger calculations serve as a warm-up for the calculations of binary black hole-neutron star (BHNS) mergers. BHNS merger calculations are more challenging because of the presence of hydrodynamic matter.

The representative calculation summarized here was performed with the Ilinois relativistic hydrodynamics code with the hydrodynamics turned "off" to solve the pure vacuum problem. The code utilizes the BSSN scheme for evolving the Einstein equations and employs AMR (adaptive mesh refinement). The initial data is "puncture" data for a BHBH binary in a quasicircular orbit and the evolution is performed with "moving puncture" gauge conditions.

Initial Configuration


Scientific visualization by

University of Illinois at Urbana-Champaign

last updated 8 July 08 by AH

Center for Theoretical Astrophysics---University of Illinois at Urbana-Champaign

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