Skip to main content# An analysis of the propagation of gravitational radiation under a graviton of nonzero mass and its implications for cosmological measurements

Presentation #110.02D in the session Gravitational Waves and Multi-messenger Astronomy.

Published onJun 19, 2024

An analysis of the propagation of gravitational radiation under a graviton of nonzero mass and its implications for cosmological measurements

Gravitational wave observation has been a boon to astronomy, revealing evidence for previously undetected systems and advancing astrophysical theory from star formation to cosmology. General relativity predicts gravitational waves to propagate via a massless mediator and therefore travel at the speed of light. The near-simultaneous detection of GW170817 and GRB170817A constrain the speed of light and the speed of gravity to be the same to one part in 10^{15}.

If we are in a universe where the mediator has some small mass, it introduces a propagation dependent effect on the gravitational wave signal which, in principle, can be detected by ground-based observatories during gravitational wave events. If the graviton is truly massless, no finite deviation will be detected and an upper limit on the mass can be placed.

This work considers the effects of a graviton of nonzero mass which imparts a redshift dependent phase shift on the observed gravitational wave signal that encodes its propagation through the Universe. The successful recovery of the redshift from this phase deviation would allow a measurement of both distance (from the amplitude of the signal) and redshift (from the phase deviation) for any gravitational wave source without relying on galaxy catalogs or observation of an electromagnetic counterpart. This simultaneous and independent measurement would allow for a constraint on the Hubble constant (H0), among other cosmological parameters, which is independent from other methods.

We simulate the detection of a population of gravitational wave signals, modified to incorporate the effect of a massive graviton, with current and future detector networks to explore the feasibility of constraining cosmological parameters with this method. Individual measurements from each simulated event are combined to yield a population-level constraint on H0.

At current LIGO-Virgo-KAGRA sensitivities, this method is limited by the precision of the redshift recovery, resulting in a one-sided measurement of H0.