Quasinormal Modes of Dirty Black Holes

TL;DR

This paper derives a perturbative formula to understand how the astrophysical environment, like accretion disks, influences the quasinormal mode spectrum of gravitational waves emitted by black holes, aiding future gravitational wave observations.

Contribution

It introduces a novel perturbative approach to quantify environmental effects on black hole quasinormal modes, extending the idealized models.

Findings

Perturbed QNM spectrum can exhibit notable features.

Environmental factors significantly shift QNM frequencies.

The model provides insights into realistic astrophysical scenarios.

Abstract

Quasinormal mode (QNM) gravitational radiation from black holes is expected to be observed in a few years. A perturbative formula is derived for the shifts in both the real and the imaginary part of the QNM frequencies away from those of an idealized isolated black hole. The formulation provides a tool for understanding how the astrophysical environment surrounding a black hole, e.g., a massive accretion disk, affects the QNM spectrum of gravitational waves. We show, in a simple model, that the perturbed QNM spectrum can have interesting features.