Strong-Field Scattering of Two Black Holes - Numerics Versus Analytics.

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Strong-Field Scattering of Two Black Holes - Numerics Versus Analytics.

Thibault Damour, Federico Guercilena, Ian Hinder, Seth Hopper, Alessandro Nagar, Luciano Rezzolla
Paper Phys. Rev. D 89:081503 (2014) | 2014-28-02

Abstract

We probe the gravitational interaction of two black holes in the strong-field regime by computing the scattering angle χ of hyperbolic-like, close binary-black-hole encounters as a function of the impact parameter. The fully general-relativistic result from numerical relativity is compared to two analytic approximations: post-Newtonian theory and the effective-one-body formalism. As the impact parameter decreases, so that black holes pass within a few times their Schwarzschild radii, we find that the post-Newtonian prediction becomes quite inaccurate, while the effective-one-body one keeps showing a good agreement with numerical results. Because we have explored a regime which is very different from the one considered so far with binaries in quasi-circular orbits, our results open a new avenue to improve analytic representations of the general-relativistic two-body Hamiltonian.