Novel category of environmental effects on gravitational waves from binaries perturbed by periodic forces

Abstract

We study the gravitational wave (GW) emission of sources perturbed by periodic dynamical forces that do not cause secular evolution in the orbital elements. We construct a corresponding post-Newtonian waveform model and provide estimates for the detectability of the resulting GW phase perturbations, for both space-based and future ground-based detectors. We validate our results by performing a set of Bayesian parameter recovery experiments with post-Newtonian waveforms. We find that, in stark contrast to the more commonly studied secular dephasing, periodic phase perturbations do not suffer from degeneracies with any of the tested vacuum binary parameters. We discuss the applications of our findings to a range of possible astrophysical scenarios, finding that such periodic perturbations may be detectable for massive black hole binaries embedded in circumbinary disks and extreme mass-ratio inspirals in accretion disks, as well as stellar-mass compact objects perturbed by tidal fields. We argue that modeling conservative suborbital dynamics opens up a promising new avenue to detect environmental effects in binary sources of GWs that should be included in state-of-the-art waveform templates.