Strong-Field Numerical Relativity in the Era of Gravitational Wave Astronomy

Abstract

The success of numerical relativity and gravitational wave detectors have paired to provide us with the opportunity to study Einstein’s theory of general relativity in the strongest gravitational regimes. With future detectors coming online with higher sensitivities, numerical relativity will need to continue to improve alongside the detectors. This dissertation addresses how numerical relativity can be used and improved to obtain the most scientific return from each gravitational wave observation. I first develop a new technique to use numerical relativity to better characterize the signals from current generation detectors by predicting the spin of the remnant black hole us- ing only the information available from the gravitational wave during merger, the loudest part of a binary black hole coalescence. This gives a way of more accurately characterizing the remnant black hole when very little inspiral is observed, and provides a new general relativity consistency test using the remnant spin determined from each stage of the coalescence. I then shift my focus towards preparing numerical relativity to detect and understand signals from next generation grav- itational wave detectors which will be much more sensitive with unique data analysis challenges. In order to produce waveform templates which are indistinguishable from true signals, numerical relativity simulations will need to be sufficiently well resolved. I construct a method to determine the necessary resolution of numerical relativity simulations as a function of signal-to-noise ratio. To accurately characterize gravitational wave signals, it is also crucial that the parameter space of binary black hole systems be densely populated with simulations. However, due to the high computational cost of numerical relativity, these simulations need to be chosen carefully. I develop methods to decrease the effective parameter space and to identify the optimal parameters for new simulations. The methods and techniques presented here help to maximize the scientific gain from each gravitational wave detection, for both present and future detectors.