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Reducing orbital eccentricity in binary black hole simulations

Harald P. Pfeiffer·Duncan A. Brown·Lawrence E. Kidder·Lee Lindblom·Geoffrey Lovelace·Mark A. Scheel
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Abstract

Binary black hole simulations starting from quasi-circular (i.e., zero radial velocity) initial data have orbits with small but non-zero orbital eccentricities. In this paper the quasi-equilibrium initial-data method is extended to allow non-zero radial velocities to be specified in binary black hole initial data. New low-eccentricity initial data are obtained by adjusting the orbital frequency and radial velocities to minimize the orbital eccentricity, and the resulting ($\sim 5$ orbit) evolutions are compared with those of quasi-circular initial data. Evolutions of the quasi-circular data clearly show eccentric orbits, with eccentricity that decays over time. The precise decay rate depends on the definition of eccentricity; if defined in terms of variations in the orbital frequency, the decay rate agrees well with the prediction of Peters (1964). The gravitational waveforms, which contain $\sim 8$ cycles in the dominant l=m=2 mode, are largely unaffected by the eccentricity of the quasi-circular initial data. The overlap between the dominant mode in the quasi-circular evolution and the same mode in the low-eccentricity evolution is about 0.99.

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Harald P. Pfeiffer, Duncan A. Brown, Lawrence E. Kidder, Lee Lindblom, Geoffrey Lovelace, Mark A. Scheel. 2007-04-25. Reducing orbital eccentricity in binary black hole simulations. https://doi.org/10.1088/0264-9381%2F24%2F12%2Fs06

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