Constraints on coasting cosmological models from gravitational-wave standard sirens

Abstract

We present the first test of coasting cosmological models with gravitational-wave standard sirens observed in the first three observing runs of the LIGO-Virgo-KAGRA detector network. We apply the statistical galaxy catalog method adapted to coasting cosmologies and infer constraints on the $H_0$ Hubble constant for the three fixed values of the curvature parameter $k=\left\{-1,0,+1\right\}$ in $H_0^2{c}^{-2}$ units. The maximum posteriors and $68.3\%$ highest density intervals we obtained from a combined analysis of $46$ dark siren detections and a single bright siren detection are $H_0=\left\{68.1_{-5.6}^{+8.5},67.5_{-5.2}^{+8.3},67.1_{-5.8}^{+6.6}\right\}\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mp}{\mathrm{c}}^{-1}$, respectively. All our constraints on $H_0$ are consistent within one sigma with the $H_0$ measured with the differential age method, which provides a constraint on $H_0$ in coasting cosmologies independently from $k$. Our results constrain all cosmological models with $a(t)\propto t$ linear expansion in the luminosity distance and redshift range of the $47$ LIGO-Virgo detections, i.e. $d_{\mathrm{L}}\lesssim 5\mathrm{Gpc}$ and $z\lesssim 0.8$, which practically include all (both strictly linear and quasi-linear) models in the coasting model family. As we have found, the coasting models and the $\hat{I}›$CDM model fit equally well to the applied set of gravitational-wave detections.

7 pages, 3 figures, 1 table