Black-hole-binary simulations and gravitational-wave astronomy

The first direct detection of gravitational waves (GW) is expected in the next few years, from a network of ground- based detectors currently taking data. One of the most promising sources for the first detection is the merger of two black holes (BHs). Identifying the signature of a merger waveform in noisy detector data requires matched filtering against a template bank of theoretical waveforms, and the only way to calculate the waves predicted by Einstein`s full general theory of relativity is to solve the equations on a computer. That is what I do. Numerical simulations of BH binaries became possible in 2005, and since then a wealth of results have been obtained relevant to mathematical relativity, BH physics, and galactic astrophysics. But only a handful of simulations have been performed for the purpose of GW detection. I have been involved in many of them, and for this project I plan to extend this study to produce a complete-enough set of numerical waveforms to allow a full mapping of all possible configurations of BH binaries following quasi-circular inspiral. The main goal of this work is to construct a phenomenological analytic model that dramatically increases the probability of detection (over current waveform approximation methods), and to make possible accurate estimation of the physical parameters of the GW source. This is an ambitious task. It requires more accurate and efficient numerical methods than are currently used, improved initial data for simulations (in particular allowing us to simulate highly-spinning BHs, which is not possible with the most popular current black-hole-binary evolution approach, the moving-puncture method), a far deeper exploration of the regime of accuracy of approximate post-Newtonian waveforms, and further insight into the properties of BHs with precessing spins. I have already completed important work in each of these areas, which I plan to continue in Vienna. The Gravity Group at the University of Vienna has a strong history of research in classical general relativity, including numerical relativity and initial-data studies. Professor Robert Beig, with whom I will work, is a leading expert in the mathematical properties of the constraint equations of general relativity, and his experience and insight will be valuable in the most theoretically challenging aspect of the projects I plan to undertake, namely the construction of better (in both an astrophysical and numerical sense) initial data.