Speaker
Description
In general relativity, gravitational waves (GW) follow null geodesics, whereas in alternative theories of gravity they may propagate along timelike geodesics. Depending on the form of the dispersion relation, this can produce amplitude distortions in chirping signals. We demonstrate this effect for the case of massive gravitons, showing that dispersion modifies the amplitude of gravitational waves in a way which is complementary to standard tests that rely on phase distortions. Applying this dark siren test of gravity to selected events from the third observing run of LIGO–Virgo–KAGRA, we obtain constraints that are competitive with phase-based dispersion tests. Our formalism therefore complements existing phase analyses and paves the way for fully consistent tests of gravitational-wave dispersion using both phase and amplitude information.