Modeling Photoionized Turbulent Material in the Circumgalactic Medium
  III: Effects of Co-rotation and Magnetic Fields
  Absorption-line measurements of the circumgalactic medium (CGM) display a
highly non-uniform distribution of lower ionization state species accompanied
by more widespread higher ionization state material. This suggests that the CGM
is a dynamic, multiphase medium, such as arises in the presence of turbulence.
To better understand this evolution, we perform hydrodynamic and
magneto-hydrodynamic (MHD) simulations of the CGM surrounding Milky Way-like
galaxies. In both cases, the CGM is initially in hydrostatic balance in a
$10^{12}$ solar masses dark matter gravitational potential, and the simulations
include rotation in the inner halo and turbulence that decreases radially. They
also track ionizations, recombinations, and species-by-species radiative
cooling in the presence of the redshift-zero UV background, employing the
MAIHEM non-equilibrium chemistry package. We find that after 9 Gyrs of
evolution, the presence of a magnetic field leads to an overall hotter CGM,
with cool gas in the center where magnetic pressure dominates. While the
non-MHD run produces more cold clouds overall, we find similar Si IV/O VI and N
V/O VI ratios between the MHD and non-MHD runs, which are both very different
from their equilibrium values. The non-MHD halo develops cool, low angular
momentum filaments above the central disk, in comparison to the MHD run that
has more efficient angular momentum transport, especially for the cold gas
which forms a more ordered and extended disk late into its evolution.
