Strong-field scattering of two spinning black holes: Numerical Relativity versus post-Minkowskian gravity

Highly accurate models of the gravitational wave signal from coalescing compact binaries are built by completing analytical computations of the binary dynamics with nonperturbative information from numerical relativity (NR) simulations. In this paper we present four sets of NR simulations of equal-mass black hole binaries that undergo strong-field scattering: (i) we reproduce and extend the nonspinning simulations first presented in [Damour et al., Strong-field scattering of two black holes: Numerics versus analytics, Phys. Rev. D 89, 081503 (2014).]; (ii) we compute two suites of nonspinning simulations at higher energies, probing stronger field interactions; (iii) we present a series of spinning simulations including, for the first time, unequal-spin configurations. When comparing the NR scattering angles to analytical predictions based on state-of-the-art post-Minkowskian (PM) calculations, we find that PM-expanded scattering angles show poor convergence towards NR data. By contrast, a resummed computation of scattering angles via a spin-dependent, radiation-reacted, effective-one-body potential shows excellent agreement for both nonspinning and spinning configurations.