  We present a mechanism for long bursts of gravitational radiation from Kerr
black holes surrounded by a torus. These systems are believed to form in
core-collapse of massive stars in association with gamma-ray bursts. The torus
catalyzes black hole-spin energy mostly into gravitational radiation, with a
minor output in winds, thermal and neutrino emissions. Torus winds impact the
remnant envelope of the progenitor star from within, which may account for
X-ray emission lines and leaves a supernova remnant. The frequency in
gravitational radiation satisfies f_{gw}=470Hz (E_{SNR}/4\times
10^{51})^{1/2}(0.1/\beta)^{1/2}(7M_\odot/M_H)^{3/2}, where E_{SNR} is the
kinetic energy in the SNR, M_H is the black hole mass and \beta\simeq0.1 the
initial ejection velocity, as detected in GRB 011211. Ultimately, this leaves a
black hole binary surrounded by a SNR, which is conceivably illustrated by RX
J050736-6847.8.
