Signatures of black hole spin in galaxy evolution
  We explore the connection between black hole spin and AGN power by addressing
the consequences underlying the assumption in the recent literature that the
gap region between accretion disks and black holes is fundamental in producing
strong, spin-dependent, horizon-threading magnetic fields. Under the additional
assumption that jets and outflows in AGN are produced by the Blandford-Znajek
and Blandford-Payne mechanisms, we show that maximum jet/outflow power is
achieved for accretion onto black holes having highly retrograde spin
parameter, an energetically excited yet unstable gravitomagnetic configuration.
