A calorimetric test for Kerr black holes in gamma-ray bursts

Cosmological gamma-ray bursts are potentially associated with systems harbo ring a rotating black hole. Calorimetry on yet "unseen" emissions in gravit ational waves from a surrounding torus may provide a measure for its rotati onal energy. We introduce a compactness parameter alpha = 2 pi integralf dE for the fluence E and frequency f in gravitational waves. For black hole-t orus systems, alpha similar or equal to 2 pi Ef similar or equal to 0.005-0 .05 may exceed the upper bound alpha = 0.005 for rapidly rotating neutron s tars. A duration in gravitational radiation consistent with the redshift-co rrected durations of the BATSE catalog defines an association with long gam ma-ray bursts. This promises to be a new test for Kerr black holes as objec ts in nature.