Polarization Tomography with Stokes Parameters
  We present a simple but powerful technique for the analysis of polarized
emission from radio galaxies and other objects. It is based on the fact that
images of Stokes parameters often contain considerably more information than is
available in polarized intensity and angle maps. In general, however, the
orientation of the Stokes parameters will not be matched to the position angles
of structures in the source. Polarization tomography, the technique presented
in this paper, consists of making a series of single linear Stokes parameter
images, $S(\rho)$, where each image is rotated by an angle $\rho$ from the
initial orientation of Q and U. Examination of these images, in a series of
still frames or a movie, reveals often hidden patterns of polarization angles,
as well as structures that were obscured by the presence of overlapping
polarized emission. We provide both cartoon examples and a quick look at the
complex polarized structure in Cygnus A.
