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Bibliographic Details
Main Authors: Habib, Sarah, Scheel, Mark, Teukolsky, Saul
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2410.05531
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author Habib, Sarah
Scheel, Mark
Teukolsky, Saul
author_facet Habib, Sarah
Scheel, Mark
Teukolsky, Saul
contents Simulation of quasicircular compact binaries is a major goal in numerical relativity, as they are expected to constitute most gravitational wave observations. However, given that orbital eccentricity is not well-defined in general relativity, providing initial data for such binaries is a challenge for numerical simulations. Most numerical relativity codes obtain initial conditions for low-eccentricity binary simulations by iterating over a sequence of short simulations -- measuring eccentricity mid-evolution and correcting the initial data parameters accordingly. Eccentricity measurement depends on a numerically challenging nonlinear fit to an estimator model, and the resulting eccentricity estimate is extremely sensitive to small changes in how the fit is performed. We have developed an improved algorithm that produces more consistent measurements of eccentricity relative to the time window chosen for fitting. The primary innovations are the use of the nonlinear optimization algorithm, variable projection, in place of more conventional routines, an initial fit parameter guess taken from the trajectory frequency spectrum, and additional frequency processing of the trajectory data prior to fitting.
format Preprint
id arxiv_https___arxiv_org_abs_2410_05531
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Eccentricity Reduction for Quasicircular Binary Evolutions
Habib, Sarah
Scheel, Mark
Teukolsky, Saul
General Relativity and Quantum Cosmology
Simulation of quasicircular compact binaries is a major goal in numerical relativity, as they are expected to constitute most gravitational wave observations. However, given that orbital eccentricity is not well-defined in general relativity, providing initial data for such binaries is a challenge for numerical simulations. Most numerical relativity codes obtain initial conditions for low-eccentricity binary simulations by iterating over a sequence of short simulations -- measuring eccentricity mid-evolution and correcting the initial data parameters accordingly. Eccentricity measurement depends on a numerically challenging nonlinear fit to an estimator model, and the resulting eccentricity estimate is extremely sensitive to small changes in how the fit is performed. We have developed an improved algorithm that produces more consistent measurements of eccentricity relative to the time window chosen for fitting. The primary innovations are the use of the nonlinear optimization algorithm, variable projection, in place of more conventional routines, an initial fit parameter guess taken from the trajectory frequency spectrum, and additional frequency processing of the trajectory data prior to fitting.
title Eccentricity Reduction for Quasicircular Binary Evolutions
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2410.05531