Inspiraling Black Holes: The Close Limit

We calculate an estimate of the gravitational radiation emitted when two equal mass black holes coalesce at the end of their binary inspiral, using several approximations based on considering the holes close to each other. A shortcoming of our method is that it is limited to models forming final holes with slow rotation, but our results clearly suggest a trend for larger angular momenta. We find that about $1\%$ of the mass energy of the pair will emerge as gravitational waves during the final stages of the collision and that a negligible fraction of the angular momentum will be radiated.