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arXiv · 2101.11015

Anomalies in the gravitational recoil of eccentric black-hole mergers with unequal mass ratios

Miren Radia·Ulrich Sperhake·Emanuele Berti·Robin Croft
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Abstract

The radiation of linear momentum imparts a recoil (or "kick") to the center of mass of a merging black hole binary system. Recent numerical relativity calculations have shown that eccentricity can lead to an approximate 25% increase in recoil velocities for equal-mass, spinning binaries with spins lying in the orbital plane ("superkick" configurations) [U Sperhake et al. Phys. Rev. D 101 (2020) 024044 (arXiv:1910.01598)]. Here we investigate the impact of nonzero eccentricity on the kick magnitude and gravitational-wave emission of nonspinning, unequal-mass black hole binaries. We confirm that nonzero eccentricities at merger can lead to kicks which are larger by up to ~25% relative to the quasicircular case. We also find that the kick velocity $v$ has an oscillatory dependence on eccentricity, that we interpret as a consequence of changes in the angle between the infall direction at merger and the apoapsis (or periapsis) direction.

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Miren Radia, Ulrich Sperhake, Emanuele Berti, Robin Croft. 2021-01-26. Anomalies in the gravitational recoil of eccentric black-hole mergers with unequal mass ratios. https://doi.org/10.1103/physrevd.103.104006

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