2003ApJ...584..937V

We analyze the topology, lifetime, and emissions of a torus around a black hole formed in hypernovae and black hole-neutron star coalescence. The torus is ab initio uniformly magnetized, represented by two counteroriented current rings, and develops a state of suspended accretion against a ``magnetic wall'' around the black hole. Magnetic stability of the torus gives rise to a new fundamental limit E_B_/E_k<0.1 for the ratio of poloidal magnetic field energy to kinetic energy, corresponding to a maximum magnetic field strength B_c≃10¹⁶G7M_☉/M_H6M_H/R²M_T/0.03M_H^1/2. The lifetime of rapid spin of the black hole, effectively defined by the timescale of dissipation of spin energy E_rotin the horizon, hereby satisfies T≃40s(M_H/7M_☉)(R/6M_H)⁴(0.03M_H/M_T) for a black hole of mass M_Hsurrounded by a torus of mass M_Tand radius R. The torus converts a major fraction E_gw/E_rot∼10% into gravitational radiation through a finite number of multipole mass moments and a smaller fraction into MeV neutrinos and baryon-rich winds. At a source distance of 100 Mpc, these emissions over N=2x10⁴ periods give rise to a characteristic strain amplitude N^1/2h_char≃6x10^–21. We argue that torus winds create an open magnetic flux tube on the black hole, which carries a minor fraction E_j/E_rot≃10^–3 in baryon-poor outflows to infinity. We conjecture that these are not high-σ outflows, owing, in part, to magnetic reconnection in surrounding current sheets. The fraction E_j/E_rot~(1)/(4)(M_H/R)⁴ is standard for a universal horizon half-opening angle θ_H≃M_H/R of the open flux tube. We identify this baryon-poor output of tens of seconds with gamma-ray bursts with contemporaneous and strongly correlated emissions in gravitational radiation, conceivably at multiple frequencies. Ultimately, this leaves a black hole binary surrounded by a supernova remnant.