A Radio Polarisation Study of Magnetic Fields in the Small Magellanic
  Cloud
  Observing the magnetic fields of low-mass interacting galaxies tells us how
they have evolved over cosmic time and their importance in galaxy evolution. We
have measured the Faraday rotation of 80 extra-galactic radio sources behind
the Small Magellanic Cloud (SMC) using the CSIRO Australia Telescope Compact
Array (ATCA) with a frequency range of 1.4 -- 3.0 GHz. Both the sensitivity of
our observations and the source density are an order of magnitude improvement
on previous Faraday rotation measurements of this galaxy. The SMC generally
produces negative rotation measures (RMs) after accounting for the Milky Way
foreground contribution, indicating that it has a mean coherent line-of-sight
magnetic field strength of $-0.3\pm0.1\mu$G, consistent with previous findings.
We detect signatures of magnetic fields extending from the north and south of
the Bar of the SMC. The random component of the SMC magnetic field has a
strength of $\sim 5\mu$G with a characteristic size-scale of magneto-ionic
turbulence $< 250$ pc, making the SMC like other low-mass interacting galaxies.
The magnetic fields of the SMC and Magellanic Bridge appear similar in
direction and strength, hinting at a connection between the two fields as part
of the hypothesised `pan-Magellanic' magnetic field.
