Status of black-hole-binary simulations for gravitational-wave detection

It is now possible to theoretically calculate the gravitational-wave signal from the inspiral, merger and ringdown of a black-hole-binary system.The late inspiral, merger and ringdown can be calculated in full general relativity using numerical methods.The numerical waveforms can then be either stitched to inspiral waveforms predicted by approximation techniques (in particular post-Newtonian calculations) that start at an arbitrarily low frequency, or used to calibrate free parameters in analytic models of the full waveforms.In this review I summarize the status of numerical-relativity (NR) waveforms that include at least ten cycles of the dominant mode of the GW signal before merger, which should be long enough to produce accurate, complete waveforms for GW observations.