The eccentricity enhancement effect of intermediate-mass-ratio-inspirals: dark matter and black hole mass

TL;DR

This paper investigates how dark matter density profiles influence the orbital eccentricity of intermediate-mass-ratio-inspirals, revealing potential for future gravitational wave observations to detect dark matter effects and black hole masses.

Contribution

It analyzes the eccentricity enhancement effect under different dark matter profiles and black hole masses, proposing a method to distinguish dark matter models via gravitational wave measurements.

Findings

Eccentricity enhancement aligns with power-law dark matter profiles.

Black hole mass affects eccentricity in the presence of dark matter spikes.

Eccentricity measurements can differentiate dark matter models at specific scales.

Abstract

It was found that the dark matter (DM) in the intermediate-mass-ratio-inspiral (IMRI) system has a significant enhancement effect on the orbital eccentricity of the stellar massive compact object, such as a black hole (BH), which may be tested by space-based gravitational wave (GW) detectors including LISA, Taiji and Tianqin in future observations \citep{2019PhRvD.100d3013Y}. In this paper, we will study the enhancement effect of the eccentricity for an IMRI under different DM density profiles and center BH masses. Our results are as follows: $(1)$ in terms of the general DM spike distribution, the enhancement of the eccentricity is basically consistent with the power-law profile, which indicates that it is reasonable to adopt the power-law profile; $(2)$ in the presence of DM spike, the different masses of the center BH will affect the eccentricity, which provides a new way for us to detect the BH's mass; $(3)$ considering the change of the eccentricity in the presence and absence of DM spike, we find that it is possible to distinguish DM models by measuring the eccentricity at the scale of about $10^{5} GM/c^{2}$.