Dancing above the abyss: Environmental effects and dark matter signatures in inspirals into massive black holes

TL;DR

This paper investigates how environmental factors like dark matter spikes and accretion disks influence gravitational wave signals from inspirals into massive black holes, highlighting observable signatures and their implications for space-based detectors.

Contribution

It provides a comprehensive analysis of environmental effects on inspiral waveforms, especially focusing on dark matter spikes and their detectability in gravitational wave observations.

Findings

Dark matter effects are generally subdominant but still observable.

Environmental effects cause measurable dephasing and waveform shifts.

Dark matter spikes could be detected with space-based gravitational wave observatories.

Abstract

In this dissertation, we look at environmental effects in extreme and intermediate mass ratio inspirals into massive black holes. In these systems, stellar mass compact objects orbit massive black holes and lose orbital energy due to gravitational wave emission and other dissipative forces. We explore environmental interactions with dark matter spikes, stellar distributions, accretion disks, and combine and compare them. We discuss the existence and properties of dark matter spikes in the presence of these environmental effects. The signatures of the environmental effects, such as the phase space flow, dephasing, deshifting of the periapse, and alignment with accretion disks, are examined. These signatures are quantified in isolated spike systems, in dry, and in wet inspirals. We generally find dark matter effects to be subdominant to the other environmental effects, but their impact on the waveform is still observable and identifiable. Lastly, the rates of inspirals and the impact of spikes are estimated. All of these results are obtained with the help of a code imripy that is published alongside. If dark matter spikes exist, they should be observable with space-based gravitational wave observatories