Numerical relativity simulation of GW150914 beyond general relativity

TL;DR

This paper presents the first numerical simulation of gravitational waves from binary black hole mergers in a higher-curvature gravity theory beyond general relativity, specifically in dynamical Chern-Simons gravity, relevant to GW150914.

Contribution

It provides the first astrophysically-relevant waveform in a beyond-GR theory, including corrections to merger, ringdown, and quasi-normal modes, extending numerical relativity to alternative gravity models.

Findings

First simulation of GW in higher-curvature gravity

Quantified corrections to waveform and ringdown spectrum

Estimated detectability thresholds for deviations from GR

Abstract

We produce the first astrophysically-relevant numerical binary black hole gravitational waveform in a higher-curvature theory of gravity beyond general relativity. We simulate a system with parameters consistent with GW150914, the first LIGO detection, in order-reduced dynamical Chern-Simons gravity, a theory with motivations in string theory and loop quantum gravity. We present results for the leading-order corrections to the merger and ringdown waveforms, as well as the ringdown quasi-normal mode spectrum. We estimate that such corrections may be discriminated in detections with signal to noise ratio $\gtrsim 180-240$, with the precise value depending on the dimension of the GR waveform family used in data analysis.