Simulations of Binary Black Hole Mergers Using Spectral Methods

TL;DR

This paper introduces advanced spectral methods and gauge choices enabling stable and accurate simulations of binary black hole mergers, including systems with unequal masses and spins, advancing numerical relativity capabilities.

Contribution

The paper presents new numerical techniques, gauge conditions, and grid structures that improve the stability and flexibility of binary black hole merger simulations.

Findings

Successful simulation of generic binary black hole systems

Effective handling of unequal masses and spins

Enhanced stability and accuracy in spectral evolution methods

Abstract

Several improvements in numerical methods and gauge choice are presented that make it possible now to perform simulations of the merger and ringdown phases of "generic" binary black-hole evolutions using the pseudo-spectral evolution code SpEC. These improvements include the use of a new damped-wave gauge condition, a new grid structure with appropriate filtering that improves stability, and better adaptivity in conforming the grid structures to the shapes and sizes of the black holes. Simulations illustrating the success of these new methods are presented for a variety of binary black-hole systems. These include fairly ``generic'' systems with unequal masses (up to 2:1 mass ratios), and spins (with magnitudes up to 0.4 M^2) pointing in various directions.