Testing the anisotropy of the universe using the simulated gravitational wave events from advanced LIGO and Virgo

TL;DR

This study explores using simulated gravitational wave events from LIGO and Virgo to test the universe's anisotropy, demonstrating that a sufficient number of GW detections can constrain anisotropic parameters as effectively as supernovae observations.

Contribution

It introduces a method to use GW standard sirens for testing cosmic anisotropy and quantifies the number of events needed for precise constraints.

Findings

Over 400 GW events can constrain anisotropic amplitude as well as supernovae.

Approximately 800 GW events are required to determine the preferred direction with similar accuracy.

GW observations can serve as a complementary approach to supernovae in cosmological anisotropy testing.

Abstract

The detection of gravitational waves (GWs) provides a powerful tool to constrain the cosmological parameters. In this paper, we investigate the possibility of using GWs as standard sirens in testing the anisotropy of the universe. We consider the GW signals produced by the coalescence of binary black hole systems and simulate hundreds of GW events from the advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo. It is found that the anisotropy of the universe can be tightly constrained if the redshift of the GW source is precisely known. The anisotropic amplitude can be constrained with an accuracy comparable to the Union2.1 complication of type-Ia supernovae if $\gtrsim 400$ GW events are observed. As for the preferred direction, $\gtrsim 800$ GW events are needed in order to achieve the accuracy of Union2.1. With 800 GW events, the probability of pseudo anisotropic signals with an amplitude comparable to Union2.1 is negligible. These results show that GWs can provide a complementary tool to supernovae in testing the anisotropy of the universe.