Prospects for probing the interaction between dark energy and dark matter using gravitational-wave dark sirens with neutron star tidal deformation

TL;DR

This study explores how third-generation gravitational wave detectors observing neutron star mergers can help constrain models of dark energy and dark matter interaction, especially when combined with CMB data, despite some limitations in constraining certain parameters.

Contribution

It demonstrates the potential of GW dark sirens to improve constraints on dark energy-dark matter interaction models and examines the impact of neutron star EoS on these constraints.

Findings

GW dark sirens tightly constrain $ m \Omega_m$ and $H_0$

Combination of GW and CMB data effectively breaks parameter degeneracies

EoS of neutron stars has limited impact on combined cosmological constraints

Abstract

Gravitational wave (GW) standard siren observations provide a rather useful tool to explore the evolution of the Universe. In this work, we wish to investigate whether dark sirens with neutron star (NS) deformation from third-generation GW detectors could help probe the interaction between dark energy and dark matter. We simulate the GW dark sirens of four detection strategies based on 3 yr observation and consider four phenomenological interacting dark energy (IDE) models to perform cosmological analysis. We find that GW dark sirens could provide tight constraints on $\Omega_{\rm m}$ and $H_0$ in the four IDE models, but do not perform well in constraining the dimensionless coupling parameter $\beta$ in models of the interaction proportional to the energy density of cold dark matter. Nevertheless, the parameter degeneracy orientations of cosmic microwave background (CMB) and GW are almost orthogonal, and thus, the combination of them could effectively break cosmological parameter degeneracies, with the constraint errors of $\beta$ being $0.00068-0.018$. In addition, we choose three typical equations of state (EoSs) of an NS, i.e., SLy, MPA1, and MS1, to investigate the effect of an NS's EoS in cosmological analysis. The stiffer EoS could give tighter constraints than the softer EoS. Nonetheless, the combination of CMB and GW dark sirens (using different EoSs of an NS) shows basically the same constraint results of cosmological parameters. We conclude that the dark sirens from 3G GW detectors would play a crucial role in helping probe the interaction between dark energy and dark matter, and the CMB+GW results are basically not affected by the EoS of an NS.