Banfield et al. present a polarization and Faraday rotation study of
the hybrid morphology radio galaxy NGC 612 (PKS 0131-36), using
Australian Telescope Compact Array observations in the 1--3 GHz
band. The results are consistent with an external Faraday screen of
ionised material close to the radio galaxy.
The image above shows the rotation
measure distribution of NGC 612 in rad/m^2. The solid black contours
show the total intensity (Stokes I) emission. The synthesised beam is
shown in the bottom left corner of the image.
In the eastern (left-hand side)
lobe, the rotation measure of the hotspot increases in magnitude
towards the leading edge, as well as changing sign (compared to the
rest of the lobe). The Faraday depolarization is also about 3 times
larger at the hotspot than elsewhere. A plausible explanation for this
is significant compression of ambient magnetised gas by the bow shock
produced by the advancing hotspot.
Full details are given in
the preprint of the
paper, which will be published in Monthly Notices of the Royal