Isotropic Heating of Galaxy Cluster Cores via Rapidly Reorienting AGN
  Jets
  AGN jets carry more than sufficient energy to stave off catastrophic cooling
of the intracluster medium (ICM) in the cores of cool-core clusters. However,
in order to prevent catastrophic cooling, the ICM must be heated in a
near-isotropic fashion and narrow bipolar jets with $P_{\rm jet}=10^{44-45}$
ergs/s, typical of radio AGNs at cluster centres, are inefficient at heating
the gas in the transverse direction to the jets. We argue that due to existent
conditions in cluster cores, the SMBHs will, in addition to accreting gas via
radiatively inefficient flows, experience short stochastic episodes of enhanced
accretion via thin discs. In general, the orientation of these accretion discs
will be misaligned with the spin axis of the black holes and the ensuing
torques will cause the black hole's spin axis (and therefore, the jet axis) to
slew and rapidly change direction. This model not only explains recent
observations showing successive generations of jet-lobes-bubbles in individual
cool-core clusters that are offset from each other in the angular direction
with respect to the cluster center, but also shows that AGN jets {\it can} heat
the cluster core nearly isotropically on the gas cooling timescale. Our model
{\it does} require that the SMBHs at the centers of cool-core clusters be
spinning relatively slowly. Torques from individual misaligned discs are
ineffective at tilting rapidly spinning black holes by more than a few degrees.
Additionally, since SMBHs that host thin accretion discs will manifest as
quasars, we predict that roughly 1--2 rich clusters within $z<0.5$ should have
quasars at their centers.
