Eccentric Binary Black Hole Simulations with Numerical Relativity

TL;DR

This paper systematically studies eccentric binary black hole mergers using numerical relativity, optimizing computational techniques, and modeling merger times as a function of eccentricity for future gravitational wave analysis.

Contribution

It introduces optimized numerical methods for simulating eccentric black hole binaries and models merger times with a post-Newtonian factor, expanding the parameter space coverage.

Findings

Merger times follow a specific post-Newtonian model with eccentricity.

Optimized gauge parameters and grid structures improve simulation accuracy.

Produced 30 simulations covering various eccentricities and mass ratios.

Abstract

We perform a systematic study of eccentric orbiting nonspinning black hole binaries. We first make a technical study of the optimal full numerical techniques to apply to these studies. We choose different gauge parameters and Courant factors, $c=dx/dt$, and find an optimal value for it of 0.45. We also find the grid structure and global resolution that optimize accuracy and speed of current computational resources. With these choices we perform a study of the merger times $t_m$ as a function of eccentricity for configurations with comparable orbital energy content and find that they are well represented by the post-Newtonian factor $F(e)=(1+73e^2/24+37e^4/96)/(1-e^2)^{7/2}$ when merger times are normalized to their quasicircular values, i.e. $t_m(e)/t_m\approx F(e)$. We then perform a systematic coverage of five small-medium eccentricities up to $e\sim0.45$ and six mass ratios up to 8.5:1 producing a total of 30 simulations covering up to 25 orbits to merger to further model merger times and as a seed to a forthcoming new systematic catalog of gravitational waveforms from eccentric binary black holes to directly perform parameter estimations of gravitational waves events.