ar X iv : a st ro - p h / 01 12 21 9 v 1 1 0 D ec 2 00 1 Gamma - ray bursts : the tip of the iceberg ? Maurice

The spin-energy E rot of a Kerr black hole surrounded by a torus may power emissions in multiple windows. The recently determined true GRB-energy E γ = 3 − 5 × 10 50 erg indicates a minor fraction E j /E rot ≃ 0.1% in baryon poor output, here considered as jets along open magnetic flux-tubes from the horizon to infinity. A major fraction E gw /E rot ≃ 5% is expected in gravitational radiation from the torus. A LIGO/VIRGO detection of α = 2π f dE gw in excess of the neutron star limit α * ≃ 0.005 promises a calorimetric test for Kerr black holes. We expect a sample of LIGO/VIRGO detections to obey the distribution of redshift corrected GRB-durations.