U. Klein et al., A RADIO-CONTINUUM STUDY OF THE MAGELLANIC CLOUDS .3. THE MAGNETIC-FIELD IN THE LMC, Astronomy and astrophysics, 271(2), 1993, pp. 402-412
Using multi-frequency radio polarization surveys made with the Parkes
64-m telescope, we have investigated the morphology of the magnetic fi
eld in the Large Magellanic Cloud (LMC). To this end, a polarization m
ap at lambda21 cm has been recently added to the existing data base, r
endering possible a polarization study of the LMC at three frequencies
. The large-scale structure of the magnetic field in the LMC is derive
d from the lambda12 cm data under the assumption that Faraday rotation
is low at this wavelength. The derived field resembles the pattern of
a trailing spiral, in accordance with the sense of rotation of the LM
C. This symmetry centre of the spiral field is roughly centred at a po
sition approximately 130 pc from the kinematical centre. The magnetic
field seems to be in the LMC and not part of any pan-Magellanic magnet
ic field. The most salient polarization structure consists of two larg
e (3-4 kpc) filaments which emerge south and south-west of the giant s
tar-forming complex 30 Dor. The analysis of the observed Faraday rotat
ion and depolarization suggests that the best explanation of the polar
ization structure is in terms of a giant magnetic loop emerging our of
the plane of LMC. This loop, characterized by a high degree of field
ordering, is possibly connecting the main disk of the LMC to the anoma
lous HI component detected recently by Luks & Rohlfs (1992). The most
extreme rotation measures appear to be associated with the anomalous H
I component. The cause for this observed peculiar structure is as yet
unclear, but a relation to the collision between the LMC and the SMC s
ome 4 .10(8) yrs ago may not be ruled out.