Polarization alignments of quasars from the JVAS/CLASS 8.4-GHz surveys

We test the hypothesis that the polarization vectors of flat-spectrum radio sources (FSRSs) from the JVAS/CLASS 8.4-GHz surveys are randomly oriented in the sky. A sample with robust polarization measurements is made with 4155 objects. Redshift information is known for 1531 of them. We performed two statistical analyses: one in two dimensions and the other in three dimensions when distance is available. We find significant large-scale alignments of polarization vectors for samples containing only quasars among the varieties of FSRS. While these correlations prove difficult to explain either by a physical effect or by biases in the data set, that the quasars that have significantly aligned polarization vectors are found in regions of the sky where optical polarization alignments were previously found is striking.