Gamma-ray bursts: the tip of the iceberg?

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 of $3-5\times 10^{50}$ erg indicates a minor fraction $E_j/E_{rot}\simeq 0.1%$ in baryon poor ouput, here considered as jets along open magnetic flux-tubes from the horizon to infinity. A major fraction $E_{gw}/E_{rot}\simeq 5%$ is expected in gravitational radiation from the torus. A LIGO/VIRGO detection of $\alpha=2\pi\int fdE_{gw}$ in excess of the neutron star limit $\alpha^*\simeq 0.005$ 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.