Head-on collision of two unequal mass black holes

We present results from the first fully nonlinear numerical calculations of the head-on collision of two unequal mass black holes. Selected waveforms of the most dominant l = 2, 3, and 4 quasinormal modes are shown, as are the total radiated energies and recoil velocities for a range of mass ratios and initial separations. Our results validate the close and distant separation limit perturbation studies, and suggest that the head-on collision scenario is not likely to produce an astrophysically significant recoil effect.