An examination of magnetized outflows from active galactic nuclei in
  galaxy clusters
  We present 3D adaptive mesh refinement MHD simulations of an isolated galaxy
cluster that include injection of kinetic, thermal, and magnetic energy via a
central active galactic nucleus (AGN) in order to study and evaluate the role
that AGN may play in producing the observed cluster-wide magnetic fields. Using
the MHD solver in FLASH 3.3, we compare several sub-resolution approaches to
the evolution of AGN, specifically focusing on large-scale jet and bubble
models. We examine the effects of magnetized outflows on the accretion history
of the black hole and cluster thermodynamic properties, discuss the ability of
various models to magnetize the cluster medium, and assess the sensitivity of
these models to their underlying subgrid parameters. We find that magnetized
jet-based models suffer a severe reduction in accretion rate compared to
hydrodynamic jets; however, bubble models remain largely unaffected. While both
jets and sporadically-placed bubbles have difficulty reproducing the observed
strength and topology of cluster magnetic fields, models based on
centrally-located bubbles come closest to observations. Finally, whereas jet
models are relatively insensitive to changes in their subgrid parameters, the
accretion rate and average magnetic field produced by the bubbles vary by as
much as an order of magnitude depending on the grid resolution and accretion
strength.
