Probing the theory of gravity with gravitational lensing of gravitational waves and galaxy surveys

TL;DR

This paper proposes a novel method combining gravitational wave lensing and galaxy surveys to test gravity theories, predicting detection within a decade and extending tests to higher redshifts with future detectors.

Contribution

It introduces a new approach to probe gravity theories by cross-correlating gravitational wave data with galaxy surveys, enabling tests across different redshifts.

Findings

Detection of gravitational lensing of gravitational waves within 10 years.

Potential to test gravity theories at higher redshifts with next-generation detectors.

Synergistic use of electromagnetic and gravitational wave observations enhances testing capabilities.

Abstract

The cross-correlation of gravitational wave strain with upcoming galaxy surveys probe theories of gravity in a new way. This method enables testing the theory of gravity by combining the effects from both gravitational lensing of gravitational waves and the propagation of gravitational waves in spacetime. We find that within 10 years, the combination of the Advanced-LIGO and VIRGO detector networks with planned galaxy surveys should detect weak gravitational lensing of gravitational waves in the low redshift Universe ($z<0.5$). With the next generation gravitational wave experiments such as Voyager, LISA, Cosmic-Explorer and Einstein Telescope, we can extend this test of the theory of gravity to larger redshifts by exploiting the synergies between electromagnetic wave and gravitational wave probes.