Gravitational waves from a dust disk around a Schwarzschild black hole

TL;DR

This paper explores how gravitational wave signals from a dust disk around a Schwarzschild black hole can reveal the disk's radius, demonstrating a method applicable to future gravitational wave observations like LISA.

Contribution

It introduces a perturbation-based approach to extract the dust disk radius from gravitational wave spectra, applicable regardless of the disk's density distribution.

Findings

The disk radius can be determined from gravitational wave power spectra.

The method works for arbitrary density distributions of the dust disk.

Potential for future observational application with LISA.

Abstract

We investigate gravitational waves from a dust disk around a Schwarzschild black hole to focus on whether we can extract any of its physical properties from a direct detection of gravitational waves. We adopt a black hole perturbation approach in a time domain, which is a satisfactory approximation to illustrate a dust disk in a supermassive black hole. We find that we can determine the radius of the disk by using the power spectrum of gravitational waves and that our method to extract the radius works for a disk of arbitrary density distribution. Therefore we believe a possibility exists for determining the radius of the disk from a direct observation of gravitational waves detected by the Laser Interferometer Space Antenna.