Inferring cosmology through the propagation of gravitational waves under the influence of a massive graviton

In General Relativity, gravitational waves propagate at the speed of light with their mediation represented as a particle in the form of a massless graviton.

We investigate the impact and observability of the presence of a massive graviton, how such a modification to GR would also modify the observed gravitational waves from astrophysical compact-object binary coalescences, and how this gravitational wave propagation effect can be used as an independent measurement of cosmological parameters, focusing on the Hubble constant.

We simulate the impact of a massive graviton on compact binary coalescence observations in a near-future LIGO-Virgo-KAGRA interferometer network through a modification to the gravitational wave phase in the post-Newtonian framework.

Our analysis finds that if we assume the presence of a graviton with a Compton wavelength of ~ 5 x 10^15 m, we can utilize a population of 50 binary black hole observations to constrain the Hubble constant to a similar precision as current gravitational wave constraints.

More sensitive GW observatories, and a larger population of observed binary coalescences, will be necessary to probe lower values in the graviton mass range more in line with current observational bounds.