Modeling the source of GW150914 with targeted numerical-relativity simulations

TL;DR

This paper models the GW150914 gravitational wave event using two independent numerical-relativity simulations, confirming the accuracy of the waveforms and demonstrating the effectiveness of targeted simulations for gravitational-wave analysis.

Contribution

It presents the first modeling of GW150914 with two independent numerical-relativity codes, validating their agreement and showcasing the potential of targeted simulations in gravitational-wave research.

Findings

Excellent agreement between the two independent simulations.

Validation of numerical-relativity methods for GW150914.

Demonstration of rapid-response targeted simulations' usefulness.

Abstract

In fall of 2015, the two LIGO detectors measured the gravitational wave signal GW150914, which originated from a pair of merging black holes. In the final 0.2 seconds (about 8 gravitational-wave cycles) before the amplitude reached its maximum, the observed signal swept up in amplitude and frequency, from 35 Hz to 150 Hz. The theoretical gravitational-wave signal for merging black holes, as predicted by general relativity, can be computed only by full numerical relativity, because analytic approximations fail near the time of merger. Moreover, the nearly-equal masses, moderate spins, and small number of orbits of GW150914 are especially straightforward and efficient to simulate with modern numerical-relativity codes. In this paper, we report the modeling of GW150914 with numerical-relativity simulations, using black-hole masses and spins consistent with those inferred from LIGO's measurement. In particular, we employ two independent numerical-relativity codes that use completely different analytical and numerical methods to model the same merging black holes and to compute the emitted gravitational waveform; we find excellent agreement between the waveforms produced by the two independent codes. These results demonstrate the validity, impact, and potential of current and future studies using rapid-response, targeted numerical-relativity simulations for better understanding gravitational-wave observations.