“…One would like to determine from this the spectra of decay products, as well as other features such as angular distributions, indicative of black hole spin. First estimates of these basic features for a spinning black hole were given in [35], and there has been a lot of work on the important problem of refining calculations of gray-body factors [188,189,190,191], [192,193,194,195,196,197,198,199,200,201,202,203,204]. However, we still lack a calculation of the gray-body factors for graviton emission from spinning black holes, and so a complete picture of black hole evolution is lacking (see [191] for the evolution in the spin-down and Schwarzschild phases).…”