Black-hole binaries, gravitational waves, and numerical relativity

TL;DR

This paper reviews recent advances in numerical relativity that enable stable simulations of black-hole mergers, crucial for understanding gravitational waves and astrophysical phenomena.

Contribution

It summarizes the recent breakthroughs in numerical relativity that have made stable black-hole merger simulations possible for the first time.

Findings

Stable, robust black-hole merger simulations achieved

Enhanced understanding of black-hole binary dynamics

Applications to gravitational-wave detection and astrophysics

Abstract

Understanding the predictions of general relativity for the dynamical interactions of two black holes has been a long-standing unsolved problem in theoretical physics. Black-hole mergers are monumental astrophysical events, releasing tremendous amounts of energy in the form of gravitational radiation, and are key sources for both ground- and space-based gravitational-wave detectors. The black-hole merger dynamics and the resulting gravitational waveforms can only be calculated through numerical simulations of Einstein's equations of general relativity. For many years, numerical relativists attempting to model these mergers encountered a host of problems, causing their codes to crash after just a fraction of a binary orbit could be simulated. Recently, however, a series of dramatic advances in numerical relativity has allowed stable, robust black-hole merger simulations. This remarkable progress in the rapidly maturing field of numerical relativity, and the new understanding of black-hole binary dynamics that is emerging is chronicled. Important applications of these fundamental physics results to astrophysics, to gravitational-wave astronomy, and in other areas are also discussed.