Ligo/Virgo searches for gravitational radiation in hypernovae

A torus around a stellar-mass Kerr black hole can emit about 10% of the spin energy of a black hole in gravitational radiation, which is potentially associated with a gamma-ray burst (GRB). Wide tori may develop buckling modes by the Papaloizou-Pringle instability and gravitational radiation-reaction forces in the Burke-Thorne approximation. Gravitational-wave experiments may discover these emissions in a fraction of nearby supernovae. This provides a test for Kerr black holes and for GRB inner engines by a comparison with the deredshifted durations of long GRBs.