We propose a quasi-local formula for the linear momentum of black-hole horizons inspired by the formalism of quasi-local horizons. We test this formula using two complementary configurations: (i) by calculating the large orbital linear momentum of the two black holes in an unequal-mass, zero-spin, quasi-circular binary and (ii) by calculating the very small recoil momentum imparted to the remnant of the head-on collision of an equal-mass, anti-aligned-spin binary. We obtain results consistent with the horizon trajectory in the orbiting case, and consistent with the net radiated linear momentum for the much smaller head-on recoil velocity.
Department, Program, or Center
School of Physics and Astronomy (COS)
B. Krishnan, C. Lousto, Y. Zlochower, Phys. Rev. D 76, 081501(R) (2007). https://doi.org/10.1103/PhysRevD.76.081501
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