[Paper Review] Tests of General Relativity with GWTC-3

The LIGO Scientific Collaboration, the Virgo Collaboration+1683 more|University of Birmingham Research Portal (University of Birmingham)|Dec 13, 2021

Pulsars and Gravitational Waves ResearchPhysics and Astronomy168 citations

TL;DR

This paper conducts tests of General Relativity using the GWTC-3 gravitational-wave event catalog, evaluating consistency with GR predictions across multiple analyses.

ABSTRACT

The ever-increasing number of detections of gravitational waves (GWs) from compact binaries by the Advanced LIGO and Advanced Virgo detectors allows us to perform ever-more sensitive tests of general relativity (GR) in the dynamical and strong-field regime of gravity. We perform a suite of tests of GR using the compact binary signals observed during the second half of the third observing run of those detectors. We restrict our analysis to the 15 confident signals that have false alarm rates $\leq 10^{-3}\, { m yr}^{-1}$. In addition to signals consistent with binary black hole (BH) mergers, the new events include GW200115_042309, a signal consistent with a neutron star--BH merger. We find the residual power, after subtracting the best fit waveform from the data for each event, to be consistent with the detector noise. Additionally, we find all the post-Newtonian deformation coefficients to be consistent with the predictions from GR, with an improvement by a factor of ~2 in the -1PN parameter. We also find that the spin-induced quadrupole moments of the binary BH constituents are consistent with those of Kerr BHs in GR. We find no evidence for dispersion of GWs, non-GR modes of polarization, or post-merger echoes in the events that were analyzed. We update the bound on the mass of the graviton, at 90% credibility, to $m_g \leq 2.42 imes 10^{-23} \mathrm{eV}/c^2$. The final mass and final spin as inferred from the pre-merger and post-merger parts of the waveform are consistent with each other. The studies of the properties of the remnant BHs, including deviations of the quasi-normal mode frequencies and damping times, show consistency with the predictions of GR. In addition to considering signals individually, we also combine results from the catalog of GW signals to calculate more precise population constraints. We find no evidence in support of physics beyond GR.

Motivation & Objective

• Motivate and assess the validity of General Relativity in the strong-field regime using GWTC-3 events.
• Combine multiple GR-consistency tests to analyze deviations from GR predictions.
• Quantify constraints on alternative theories or parametrized deviations from GR.
• Assess robustness of results against waveform models and data quality across the GWTC-3 catalog.

Proposed method

• Apply GR-consistency tests to GWTC-3 events.
• Use parametrized deviations and posterior analyses to constrain possible GR violations.
• Cross-check results with different waveform models and data conditioning.
• Aggregate results to produce global constraints on deviations from GR.

Experimental results

Research questions

• RQ1 Do GWTC-3 events show consistency with General Relativity across multiple waveform analyses and tests?
• RQ2 What are the constraints on deviations from GR allowed by the GWTC-3 data?
• RQ3 How robust are GR tests to waveform systematics and modeling choices within GWTC-3?
• RQ4 Can the GWTC-3 data reveal any statistically significant tension with GR predictions?

Key findings

• GR-consistency is reported across the GWTC-3 dataset within the tested deviation frameworks.
• Constraints on parametrized deviations from GR are placed using the GWTC-3 events.
• Results are checked for robustness against waveform models and data quality selections.
• No statistically significant violations of GR are claimed within the analyzed framework and data.