Unusual Polarization Angle swing of OJ 287

ABSTRACT :
We present the results of multi-frequency polarimetric monitoring of the blazar OJ 287 with the Korean VLBI Network (KVN) at 22-129 GHz and the Atacama Large Millimeter/submillimeter Array (ALMA) at 90-350 GHz. Polarization angle of OJ 287 swings by more than 300 degrees over the period 2016-2017. This unusual polarization angle swing is accompanied by repeating radio flares that increase in magnitude with each occurrence. Such repeating radio flares are thought to originate from either Doppler boosting of the moving jet component or from shocks occurring when moving jet components pass through stationary recollimation shocks. In either case, this implies a potential connection between the swing of the polarization angle and the motion of the jet components. We discuss several types of jet motion that could lead to such an unusual polarization angle swing and the mechanisms that might account for the jet component motions.