Merger states and final states of black hole coalescences: a numerical-relativity-assisted effective-one-body approach

TL;DR

This paper compares effective-one-body predictions with numerical relativity data for nonspinning binary black hole mergers, confirming high accuracy in energy and angular momentum estimates and providing new analytical fits for final black hole properties.

Contribution

It demonstrates the high accuracy of the effective-one-body approach in modeling black hole coalescences and offers new analytical fits for final mass and spin across all mass ratios.

Findings

Effective-one-body predictions agree with numerical relativity at the per mil level.

The approach accurately describes the system's energy and angular momentum at merger and final state.

Provides analytical fits for final black hole mass and spin for all mass ratios.

Abstract

We study to what extent the effective-one-body description of the dynamical state of a nonspinning, coalescing binary black hole (considered either at merger, or after ringdown) agrees with numerical relativity results. This comparison uses estimates of the integrated losses of energy and angular momentum during ringdown, inferred from recent numerical-relativity data. We find that the values, predicted by the effective-one-body formalism, of the energy and angular momentum of the system agree at the per mil level with their numerical-relativity counterparts, both at merger and in the final state. This gives a new confirmation of the ability of effective-one-body theory to accurately describe the dynamics of binary black holes even in the strong-gravitational-field regime. Our work also provides predictions (and analytical fits) for the final mass and the final spin of coalescing black holes for all mass ratios