Evolution of Binary Black Hole Spacetimes

TL;DR

This paper demonstrates the successful numerical evolution of binary black hole spacetimes using a generalized harmonic coordinate scheme, enabling analysis of orbits, mergers, and gravitational wave emission.

Contribution

It introduces a numerical method based on generalized harmonic coordinates that can simulate binary black hole mergers over sufficient time to study gravitational waves.

Findings

Binary black hole evolution achieved with the new scheme.

Estimated black hole spin parameter after merger is ~0.70.

Approximate 5% of system mass radiated as gravitational waves.

Abstract

We describe early success in the evolution of binary black hole spacetimes with a numerical code based on a generalization of harmonic coordinates. Indications are that with sufficient resolution this scheme is capable of evolving binary systems for enough time to extract information about the orbit, merger and gravitational waves emitted during the event. As an example we show results from the evolution of a binary composed of two equal mass, non-spinning black holes, through a single plunge-orbit, merger and ring down. The resultant black hole is estimated to be a Kerr black hole with angular momentum parameter a~0.70. At present, lack of resolution far from the binary prevents an accurate estimate of the energy emitted, though a rough calculation suggests on the order of 5% of the initial rest mass of the system is radiated as gravitational waves during the final orbit and ringdown.