Proposed source of gravitational radiation from a torus around a black hole.

Long gamma-ray bursts (GRBs) could be emitted from rapidly spinning black-hole-torus systems, resulting from either hypernovae or black-hole-neutron-star coalescence. We show that a nonaxisymmetric torus may also radiate gravitational radiation, powered by the spin energy of the black hole. The coupling to the spin energy of the black hole operates by equivalence in poloidal topology to pulsar magnetospheres. Results calculated in the suspended-accretion state indicate that GRBs are potentially the most powerful LIGO/VIRGO burst sources in the Universe, with an expected duration of 10-15 s on a horizontal branch of 1-2 kHz in the f(f) diagram.