Neutral hydrogen and magnetic fields in M83 observed with the SKA
  Pathfinder KAT-7
  We present new KAT-7 observations of the neutral hydrogen (HI) spectral line,
and polarized radio continuum emission, in the grand design spiral M83. These
observations provide a sensitive probe of the outer disk structure and
kinematics, revealing a vast and massive neutral gas distribution that appears
to be tightly coupled to the interaction of the galaxy with the environment. We
present a new rotation curve extending out to a radius of 50 kpc. Based on our
new HI dataset and comparison with multiwavelength data from the literature we
consider the impact of mergers on the outer disk and discuss the evolution of
M83. We also study the periphery of the HI distribution and reveal a sharp edge
to the gaseous disk that is consistent with photoionization or ram pressure
from the intergalactic medium (IGM). The radio continuum emission is not nearly
as extended as the HI and is restricted to the main optical disk. Despite the
relatively low angular resolution we are able to draw broad conclusions about
the large-scale magnetic field topology. We show that the magnetic field of M83
is similar in form to other nearby star forming galaxies, and suggest that the
disk-halo interface may host a large-scale regular magnetic field.
