Plunge waveforms from inspiralling binary black holes

We study the coalescence of non-spinning binary black holes from the innermost stable circular orbit down to the final single rotating black hole. We use a technique that combines the full numerical approach to solve Einstein equations, applied in the truly nonlinear regime, and linearized perturbation theory around the final distorted single black hole at later times. We compute the plunge waveforms which present a non negligible signal lasting for over $tsim 100$M showing early nonlinear ringing. We also obtain estimates of the total gravitational energy radiated during this process and the plunging time