Gravitational self-force on eccentric equatorial orbits around a Kerr black hole

TL;DR

This paper calculates the first-order gravitational self-force on a small object in an eccentric equatorial orbit around a Kerr black hole, advancing understanding of orbital dynamics in strong gravity.

Contribution

It introduces a novel method to compute the gravitational self-force on eccentric equatorial Kerr orbits, including both conservative and dissipative effects, using solutions of the Teukolsky equation.

Findings

First calculation of self-force on eccentric Kerr orbits

Verification of the balance law for energy and angular momentum

Identification of convergence issues in frequency domain calculations

Abstract

This paper presents the first calculation of the gravitational self-force on a small compact object on an eccentric equatorial orbit around a Kerr black hole to first order in the mass-ratio. That is the pointwise correction to the object's equations of motion (both conservative and dissipative) due to its own gravitational field treated as a linear perturbation to the background Kerr spacetime generated by the much larger spinning black hole. The calculation builds on recent advances on constructing the local metric and self-force from solutions of the Teukolsky equation, which led to the calculation of the Detweiler-Barack-Sago redshift invariant on eccentric equatorial orbits around a Kerr black hole in a previous paper. After deriving the necessary expression to obtain the self-force from the Weyl scalar $\psi_4$, we perform several consistency checks of the method and numerical implementation, including a check of the balance law relating orbital average of the self-force to average flux of energy and angular momentum out of the system. Particular attention is paid to the pointwise convergence properties of the sum over frequency modes in our method, identifying a systematic inherent loss of precision that any frequency domain calculation of the self-force on eccentric orbits must overcome.