Testing the Alignment Tendency of Some Polarized Radio Sources
  Measuring the alignment of polarized radio sources requires comparing vectors
at different locations on the sky, i.e. on a sphere. A test of alignment is
derived herein. While both large scale and coordinate independent, the test
avoids the mathematical subtleties involved when comparing vectors at different
locations on a curved surface. Applied to 5442 sources drawn from a published
catalog, the analysis finds a level of alignment that would be matched by only
7% to 14% of data sets with the same sources but with random polarization
directions. The locations of the sources involved and the directions that the
vectors favor and the regions avoided are described as well.
