An Intrinsic Model for the Polarization Position Angle Swing Observed in QSO 1150+812

Abstract

The rapid polarization position angle swing of ∼ 180° observed in QSO 1150+812 at 2cm by Kochenov and Gabuzda is quite a regular event. One interesting property of the event is that, during the time of the swing the polarized flux density remained almost constant. We suggest that such an event can be explained in terms of a relativistic thin shock propagating through a uniform helical magnetic field, giving rise to relativistic aberration effects as the transverse field component rotates. The model may also be applicable to other similar events in which variations in polarization are not accompanied by variations in total flux density.