Magnetic Field Structure of the Large Magellanic Cloud from Faraday
  Rotation Measures of Diffuse Polarized Emission
  We present a study of the magnetic field of the Large Magellanic Cloud (LMC),
carried out using diffuse polarized synchrotron emission data at 1.4 GHz
acquired at the Parkes Radio Telescope and the Australia Telescope Compact
Array. The observed diffuse polarized emission is likely to originate above the
LMC disk on the near side of the galaxy. Consistent negative rotation measures
(RMs) derived from the diffuse emission indicate that the line-of-sight
magnetic field in the LMC's near-side halo is directed coherently away from us.
In combination with RMs of extragalactic sources that lie behind the galaxy, we
show that the LMC's large scale magnetic field is likely to be of quadrupolar
geometry, consistent with the prediction of dynamo theory. On smaller scales,
we identify two brightly polarized filaments southeast of the LMC, associated
with neutral hydrogen arms. The filaments' magnetic field potentially aligns
with the direction towards the Small Magellanic Cloud. We suggest that tidal
interactions between the Small and the Large Magellanic Clouds in the past 10^9
years is likely to have shaped the magnetic field in these filaments.
