One of the simplest tests consists in measuring the polarization of a new sample of quasars located in one of the regions of the sky where an alignment was previously found and where we can predict in advance the range of polarization position angles. Such polarimetric observations have been recently carried out, and the results are presented here. 2, we present the new polarimetric observations, as well as a compilation of the most recent measurements from the literature. Then, from the properties of the objects in the region of alignment we derive some constraints on possible interpretations. These are discussed in Sect.
Conclusions form the last section.