Gravitational-wave standard siren without redshift identification

TL;DR

This paper explores how future space-based gravitational-wave detectors can measure cosmological expansion and dark energy properties using neutron-star binaries without needing redshift data from electromagnetic observations.

Contribution

It demonstrates the potential of GW standard sirens to probe dark energy independently of electromagnetic redshift measurements, expanding cosmological analysis methods.

Findings

High-precision luminosity distance measurements enable cosmological constraints.

Dark energy parameters can be constrained without electromagnetic redshift data.

Comparison shows advantages over traditional electromagnetic methods.

Abstract

Proposed space-based gravitational-wave (GW) detectors such as DECIGO and BBO will detect $\sim10^6$ neutron-star (NS) binaries and determine the luminosity distances to the binaries with high precision. Combining the luminosity distances with cosmologically-induced phase corrections on the GWs, cosmological expansion out to high redshift can be measured without the redshift determinations of host galaxies by electromagnetic observation and can be a unique probe for dark energy. This article is based on the results obtained in [1] where we investigated constraining power of the GW standard siren without redshift information on the equation of state of dark energy with future space-based GW detectors. We also compare the results with those obtained with other instruments and methods.