Constraints on the astrophysical environment of binaries with gravitational-wave observations

TL;DR

This paper explores how gravitational-wave observations can reveal details about the environment surrounding merging compact binaries, such as dark matter density, by analyzing phase modifications in the signals.

Contribution

It introduces a parametrization of environmental effects on gravitational-wave signals and assesses the capability of current and future detectors to constrain these effects.

Findings

Current detectors can constrain medium densities below accretion disk levels.

Future detectors like LISA can probe densities typical of dark matter.

Environmental effects can induce detectable phase dephasing in gravitational signals.

Abstract

The dynamics of coalescing compact binaries can be affected by the environment in which the systems evolve, leaving detectable signatures into the emitted gravitational signal. In this paper we investigate the ability of gravitational-wave detectors to constrain the nature of the environment in which compact binaries merge. We parametrize a variety of environmental effects by modifying the phase of the gravitational signal emitted by black hole and neutron star binaries. We infer the bounds on such effects by current and future generation of interferometers, studying their dependence on the binary's parameters. We show that the strong dephasing induced by accretion and dynamical friction can constraint the density of the surrounding medium to orders of magnitude below that of accretion disks. Planned detectors, such as LISA or DECIGO, will be able to probe densities typical of those of dark matter.