Transition from adiabatic inspiral to plunge for eccentric binaries

Fuente: arXiv
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Main Authors: Becker, Devin R., Hughes, Scott A.
Format: Preprint
Published: 2024
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author Becker, Devin R.
Hughes, Scott A.
author_facet Becker, Devin R.
Hughes, Scott A.
contents Black hole binaries with small mass ratios will be critical targets for the forthcoming Laser Interferometer Space Antenna (LISA) mission. They also serve as useful tools for understanding the properties of binaries at general mass ratios. In its early stages, such a binary's gravitational-wave-driven inspiral can be modeled as the smaller body flowing through a sequence of geodesic orbits of the larger black hole's spacetime. Its motion through this sequence is determined by the rate at which backreaction changes an orbit's integrals of motion $E$, $L_z$, and $Q$. Key to the motion being close to a geodesic at any moment is the idea that the effect of backreaction is small compared to a ``restoring force'' arising from the potential which governs geodesic motion. This restoring force holds the small body on a geodesic trajectory as the backreaction causes that geodesic to slowly evolve. As the inspiraling body approaches the last stable orbit (LSO), the restoring force becomes weaker and the backreaction becomes stronger. Once the small body evolves past the LSO, its trajectory converges to a plunging geodesic. This work aims to smoothly connect these two disparate regimes: the slowly evolving adiabatic inspiral and the final plunge. Past work has focused on this transition to plunge for circular systems. Here, we study the transition for binaries with eccentricity. A well-defined eccentric transition will make it possible to develop small-mass-ratio binary waveform models that terminate in a physically reasonable way, rather than abruptly terminating as an inspiral-only model ends. A model that can explore the parameter space of eccentricity may also be useful for understanding the final cycles of eccentric binaries at less extreme mass ratios, such as those likely to be observed by ground-based detectors.
format Preprint
id arxiv_https___arxiv_org_abs_2410_09160
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Transition from adiabatic inspiral to plunge for eccentric binaries
Becker, Devin R.
Hughes, Scott A.
General Relativity and Quantum Cosmology
High Energy Astrophysical Phenomena
Black hole binaries with small mass ratios will be critical targets for the forthcoming Laser Interferometer Space Antenna (LISA) mission. They also serve as useful tools for understanding the properties of binaries at general mass ratios. In its early stages, such a binary's gravitational-wave-driven inspiral can be modeled as the smaller body flowing through a sequence of geodesic orbits of the larger black hole's spacetime. Its motion through this sequence is determined by the rate at which backreaction changes an orbit's integrals of motion $E$, $L_z$, and $Q$. Key to the motion being close to a geodesic at any moment is the idea that the effect of backreaction is small compared to a ``restoring force'' arising from the potential which governs geodesic motion. This restoring force holds the small body on a geodesic trajectory as the backreaction causes that geodesic to slowly evolve. As the inspiraling body approaches the last stable orbit (LSO), the restoring force becomes weaker and the backreaction becomes stronger. Once the small body evolves past the LSO, its trajectory converges to a plunging geodesic. This work aims to smoothly connect these two disparate regimes: the slowly evolving adiabatic inspiral and the final plunge. Past work has focused on this transition to plunge for circular systems. Here, we study the transition for binaries with eccentricity. A well-defined eccentric transition will make it possible to develop small-mass-ratio binary waveform models that terminate in a physically reasonable way, rather than abruptly terminating as an inspiral-only model ends. A model that can explore the parameter space of eccentricity may also be useful for understanding the final cycles of eccentric binaries at less extreme mass ratios, such as those likely to be observed by ground-based detectors.
title Transition from adiabatic inspiral to plunge for eccentric binaries
topic General Relativity and Quantum Cosmology
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2410.09160