(ed.). Gravitational waves (IOP, 2001)(422s).

398 Numerical relativityFigure 18.4. We show a sequence of visualizations of the merger of two black holeswith unequal mass and spin. The apparent horizons are shown as the surfaces at thecentre of the image, and the colours represent the Gaussian curvature. The waves, shownemanating from the merger, are visualizations of the real part of the Newman–Penrosequantity 4 . The top left-hand panel shows the system just before the merger, while thebottom right-hand panel shows the system much later.techniques, such as black hole excision, these simulations will be limited to thefinal merger phase of black hole coalescence. Hence, it is important that thecommunity continue to focus on this long term solution. However, while that isunder development, we can take advantage of our capabilities and explore thisphase of the inspiral now. Our goal is several fold: (a) to explore new black holephysics of the ‘final plunge’ phase of the binary BH merger; (b) to try to determinesome useful information relevant for gravitational-wave astronomy; and (c) toprovide a strong foundation of knowledge for this process that will be useful whenmore advanced techniques, such a black hole excision, are fully developed. When