Cosmology with Gravitational Wave/Fast Radio Burst Associations

TL;DR

This paper explores using associations between gravitational waves and fast radio bursts as a new, H0-independent method for cosmology, demonstrating through simulations that it can effectively constrain cosmological parameters with around 100 systems.

Contribution

It introduces a novel combined GW/FRB standard siren method, $D_{L}\cdot{\rm DM_{IGM}}$, which improves cosmological constraints and is independent of the Hubble constant.

Findings

The $D_{L}\cdot{\rm DM_{IGM}}$ method outperforms traditional methods in constraining cosmology.

Simulations show effective parameter constraints with about 100 GW/FRB systems.

The methodology remains applicable even without direct GW/FRB associations.

Abstract

Recently, some theoretical models predicted that a small fraction of fast radio bursts (FRBs) could be associated with gravitational waves (GWs). In this work, we discuss the possibility of using GW/FRB association systems, if commonly detected in the future, as a complementary cosmic probe. We propose that upgraded standard sirens can be constructed from the joint measurements of luminosity distances $D_{L}$ derived from GWs and dispersion measures ${\rm DM_{IGM}}$ derived from FRBs (i.e., the combination $D_{L}\cdot{\rm DM_{IGM}}$). Moreover, unlike the traditional standard-siren approach (i.e., the $D_{L}$ method) and the $\rm DM_{IGM}$ method that rely on the optimization of the Hubble constant $H_0$, this $D_{L}\cdot{\rm DM_{IGM}}$ method has the advantage of being independent of $H_0$. Through Monte Carlo simulations, we prove that the $D_{L}\cdot{\rm DM_{IGM}}$ method is more effective to constrain cosmological parameters than $D_{L}$ or ${\rm DM_{IGM}}$ separately, and enables us to achieve accurate multimessenger cosmology from around 100 GW/FRB systems. Additionally, even if GW/FRB associations are not exist, the methodology developed here can still be applied to those GWs and FRBs that occur at the same redshifts.