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arXiv · 0707.0135

Exploring black hole superkicks

Bernd Bruegmann·Jose Gonzalez·Mark Hannam·Sascha Husa·Ulrich Sperhake
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Abstract

Recent calculations of the recoil velocity in black-hole binary mergers have found kick velocities of $\approx2500 $km/s for equal-mass binaries with anti-aligned initial spins in the orbital plane. In general the dynamics of spinning black holes can be extremely complicated and are difficult to analyze and understand. In contrast, the ``superkick'' configuration is an example with a high degree of symmetry that also exhibits exciting physics. We exploit the simplicity of this ``test case'' to study more closely the role of spin in black-hole recoil and find that: the recoil is with good accuracy proportional to the difference between the $(l = 2, m = \pm 2)$ modes of $Ψ_4$, the major contribution to the recoil occurs within $30M$ before and after the merger, and that this is after the time at which a standard post-Newtonian treatment breaks down. We also discuss consequences of the $(l = 2, m = \pm 2)$ asymmetry in the gravitational wave signal for the angular dependence of the SNR and the mismatch of the gravitational wave signals corresponding to the north and south poles.

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Bernd Bruegmann, Jose Gonzalez, Mark Hannam, Sascha Husa, Ulrich Sperhake. 2007-07-02. Exploring black hole superkicks. https://doi.org/10.1103/physrevd.77.124047

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