Connecting turbulent velocities and magnetic fields in galaxy cluster
  simulations with active galactic nuclei jets
  The study of velocity fields of the hot gas in galaxy clusters can help to
unravel details of microphysics on small-scales and to decipher the nature of
feedback by active galactic nuclei (AGN). Likewise, magnetic fields as traced
by Faraday rotation measurements (RMs) inform about their impact on gas
dynamics as well as on cosmic ray production and transport. We investigate the
inherent relationship between large-scale gas kinematics and magnetic fields
through non-radiative magnetohydrodynamical simulations of the creation,
evolution and disruption of AGN jet-inflated lobes in an isolated Perseus-like
galaxy cluster, with and without pre-existing turbulence. In particular, we
connect cluster velocity measurements with mock RM maps to highlight their
underlying physical connection, which opens up the possibility of comparing
turbulence levels in two different observables. For single jet outbursts, we
find only a local impact on the velocity field, i.e. the associated increase in
velocity dispersion is not volume-filling. Furthermore, in a setup with
pre-existing turbulence, this increase in velocity dispersion is largely
hidden. We use mock X-ray observations to show that at arcmin resolution, the
velocity dispersion is therefore dominated by existing large-scale turbulence
and is only minimally altered by the presence of a jet. For the velocity
structure of central gas uplifted by buoyantly rising lobes, we find fast,
coherent outflows with low velocity dispersion. Our results highlight that
projected velocity distributions show complex structures which pose challenges
for the interpretation of observations.
