We present results on the mass and spin of the final black hole from mergers of equal mass , spinning black holes .
The study extends over a broad range of initial orbital configurations , from direct plunges to quasi-circular inspirals to more energetic orbits ( generalizations of Newtonian elliptical orbits ) .
It provides a comprehensive search of those configurations that maximize the final spin of the remnant black hole .
We estimate that the final spin can reach a maximum spin a / M _ { h } \approx 0.99 \pm 0.01 for extremal black hole mergers .
In addition , we find that , as one increases the orbital angular momentum from small values , the mergers produce black holes with mass and spin parameters \ { M _ { h } / M,a / M _ { h } \ } spiraling around the values \ { \widehat { M } _ { h } / M, \hat { a } / M _ { h } \ } of a golden black hole .
Specifically , ( M _ { h } - \widehat { M } _ { h } ) / M \propto e ^ { \pm B \phi } \cos { \phi } and ( a - \hat { a } ) / M _ { h } \propto e ^ { \pm C \phi } \sin { \phi } , with \phi a monotonically growing function of the initial orbital angular momentum .
We find that the values of the parameters for the golden black hole are those of the final black hole obtained from the merger of a binary with the corresponding spinning black holes in a quasi-circular inspiral .