Wide field polarimetry around the Perseus cluster at 350 MHz
  This paper investigates the fascinating diffuse polarization structures at
350 MHz that have previously been tentatively attributed to the Perseus cluster
and, more specifically, tries to find out whether the structures are located at
(or near) the Perseus cluster, or in the Milky Way. A wide field, eight point
Westerbork Synthesis Radio Telescope mosaic of the area around the Perseus
cluster was observed in full polarization. The frequency range was 324 to 378
MHz and the resolution of the polarization maps was 2'x3'. The maps were
processed using Faraday rotation measure synthesis to counter bandwidth
depolarization. The RM-cube covers Faraday depths of -384 to +381 rad m^{-2} in
steps of 3 rad m^{-2}. There is emission all over the field at Faraday depths
between -50 and +100 rad m^{-2}. All previously observed structures were
detected. However, no compelling evidence was found supporting association of
those structures with either the Perseus cluster or large scale structure
formation gas flows in the Perseus-Pisces super cluster. On the contrary, one
of the structures is clearly associated with a Galactic depolarization canal at
1.41 GHz. Another large structure in polarized intensity, as well as Faraday
depth at a Faraday depth of +30 rad m^{-2}, coincides with a dark object in
WHAM H-alpha maps at a kinematic distance of 0.5 \pm 0.5 kpc. All diffuse
polarized emission at 350 MHz towards the Perseus cluster is most likely
located within 1 kpc from the Sun. The layers that emit the polarized radiation
are less than 40 pc/B|| thick.
