Computing the merger of black-hole binaries: the IBBH problem

TL;DR

This paper introduces new numerical-relativity techniques to simulate the last stages of binary black hole inspiral, addressing a key obstacle in gravitational wave detection and analysis.

Contribution

It proposes innovative methods for evolving binary black holes through their final orbits, improving the accuracy of gravitational wave modeling.

Findings

New co-rotating coordinate system for stable evolution

Techniques to isolate gravitational wave degrees of freedom

Enhanced simulation of black hole mergers

Abstract

Gravitational radiation arising from the inspiral and merger of binary black holes (BBH's) is a promising candidate for detection by kilometer-scale interferometric gravitational wave observatories. This paper discusses a serious obstacle to searches for such radiation and to the interpretation of any observed waves: the inability of current computational techniques to evolve a BBH through its last ~10 orbits of inspiral (~100 radians of gravitational-wave phase). A new set of numerical-relativity techniques is proposed for solving this ``Intermediate Binary Black Hole'' (IBBH) problem: (i) numerical evolutions performed in coordinates co-rotating with the BBH, in which the metric coefficients evolve on the long timescale of inspiral, and (ii) techniques for mathematically freezing out gravitational degrees of freedom that are not excited by the waves.