Relativistic Corrections to the Formation Rate of Extreme Mass-Ratio Inspirals

Fuente: arXiv
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Main Authors: Feng, Chen, Tang, Yong
Format: Preprint
Published: 2026
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author Feng, Chen
Tang, Yong
author_facet Feng, Chen
Tang, Yong
contents Extreme mass-ratio inspirals (EMRIs) are long-duration gravitational-wave sources in which a compact object gradually spirals into a massive black hole. Their formation is governed by the interplay between stochastic angular-momentum diffusion driven by two-body relaxation and the dissipative evolution caused by gravitational-wave emission, with the loss-cone boundary deciding whether an object undergoes an inspiral or a direct plunge. Building on this physical picture, we construct a relativistically self-consistent analytic framework for estimating EMRI event rates. In Schwarzschild spacetime, we generalize the standard loss-cone angular momentum to an energy-dependent quantity and revise the plunge pericenter by using the minimum stable radius derived from general relativity. Relative to the Newtonian treatment, we show that incorporating these relativistic effects increases the predicted EMRI rates by roughly a factor of 8. This enhancement becomes more pronounced for shallower stellar density profiles and is insensitive to the mass of the central massive black hole, which emphasizes that relativistic effects are essential for EMRI rate estimations that are relevant for space-based gravitational-wave detectors, such as LISA and Taiji.
format Preprint
id arxiv_https___arxiv_org_abs_2603_09547
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Relativistic Corrections to the Formation Rate of Extreme Mass-Ratio Inspirals
Feng, Chen
Tang, Yong
General Relativity and Quantum Cosmology
Astrophysics of Galaxies
Extreme mass-ratio inspirals (EMRIs) are long-duration gravitational-wave sources in which a compact object gradually spirals into a massive black hole. Their formation is governed by the interplay between stochastic angular-momentum diffusion driven by two-body relaxation and the dissipative evolution caused by gravitational-wave emission, with the loss-cone boundary deciding whether an object undergoes an inspiral or a direct plunge. Building on this physical picture, we construct a relativistically self-consistent analytic framework for estimating EMRI event rates. In Schwarzschild spacetime, we generalize the standard loss-cone angular momentum to an energy-dependent quantity and revise the plunge pericenter by using the minimum stable radius derived from general relativity. Relative to the Newtonian treatment, we show that incorporating these relativistic effects increases the predicted EMRI rates by roughly a factor of 8. This enhancement becomes more pronounced for shallower stellar density profiles and is insensitive to the mass of the central massive black hole, which emphasizes that relativistic effects are essential for EMRI rate estimations that are relevant for space-based gravitational-wave detectors, such as LISA and Taiji.
title Relativistic Corrections to the Formation Rate of Extreme Mass-Ratio Inspirals
topic General Relativity and Quantum Cosmology
Astrophysics of Galaxies
url https://arxiv.org/abs/2603.09547