Comparing Accretion Disks and Dark Matter Spikes in Intermediate Mass Ratio Inspirals

TL;DR

This paper models the combined effects of accretion disks and dark matter spikes on intermediate mass ratio inspirals, providing methods to distinguish their signatures in gravitational wave signals for future space-based detectors.

Contribution

It is the first to simulate an IMRI system with both an accretion disk and a dark matter spike, analyzing their distinct impacts on gravitational wave signals.

Findings

Eccentricity evolution differs between disk and DM spike influences

Braking index and dephasing index serve as complementary observational signatures

Methods to disentangle environmental effects in gravitational wave data

Abstract

Intermediate Mass Ratio Inspirals (IMRIs) will be observable with space-based gravitational wave detectors such as the Laser Interferometer Space Antenna (LISA). To this end, the environmental effects in such systems have to be modeled and understood. These effects can include (baryonic) accretion disks and dark matter (DM) overdensities, so called spikes. For the first time, we model an IMRI system with both an accretion disk and a DM spike present and compare their effects on the inspiral and the emitted gravitational wave signal. We study the eccentricity evolution, employ the braking index and derive the dephasing index, which turn out to be complementary observational signatures. They allow us to disentangle the accretion disk and DM spike effects in the IMRI system.