Merger states and final states of black hole coalescences: Comparing effective-one-body and numerical-relativity

We compute the effective-one-body predictions for the dynamical state (energy and angular momentum) of a nonspinning, coalescing binary black hole at merger. We compare these predictions to estimates of the dynamical state at merger inferred from numerical-relativity data. We find agreement at the per mil level between effective-one-body and numerical-relativity results. This gives a new confirmation of the ability of effective-one-body theory to accurately describe not only the gravitational wave emission but also 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, as well as analytical fits for the losses of energy and angular momentum during ringdown.