Cosmological Constraints from GW-FRB Associations without Redshift Measurements for LIGO-Virgo and Cosmic Explorer

TL;DR

This paper presents a redshift-independent method to constrain cosmological parameters using GW-FRB associations, emphasizing the importance of next-generation detectors like Cosmic Explorer for precise cosmology.

Contribution

Develops a framework that uses luminosity distance and dispersion measure relations to constrain cosmology without redshift measurements, comparing current and future GW detectors.

Findings

Current LIGO-Virgo network cannot provide meaningful cosmological constraints.

Cosmic Explorer can enable high-precision, redshift-independent cosmology.

Including host galaxy dispersion measures improves parameter constraints.

Abstract

The potential association between gravitational waves (GWs) and fast radio bursts (FRBs) offers a unique multi-messenger probe for cosmology. In this paper, we develop a redshift-independent framework to constrain cosmological parameters using the luminosity distance - dispersion measure relation, accounting for realistic astrophysical uncertainties. We perform a comprehensive comparative analysis across different GWs detector sensitivities and modeling assumptions. Specifically, we investigate the performance of the current LIGO-Virgo (LV) network (at $z < 0.2$) versus the future Cosmic Explorer (CE). Our study further evaluates the impact of different dispersion measure (DM) distributions -- specifically the corrected Macquart's PDF (Zhuge+2025) and the log-normal distribution -- and explores the influence of including or excluding host galaxy DM contributions. Using realistic simulated observations, we find that while the current LV network lacks the precision to provide meaningful constraints, CE will enable high-precision cosmology. Even without spectroscopic redshifts, CE observations can effectively break parameter degeneracies and robustly constrain both cosmology and host galaxy parameters. These results highlight the necessity of next-generation detectors.