Optical polarization can be an important probe of particle acceleration and high-energy emission processes in relativistic jets from supermassive black holes. Here, we combine publicly available observations from three past blazar monitoring programs to produce densely sampled light curves for 15 blazars in order to explore the relation of gamma-ray activity to the polarization variability as well as discover new rotations of the polarization angle. We find that polarization degree does not correlate with gamma-ray flux either for individual sources or different sub-samples of blazars, potentially indicating multiple emission mechanisms. In the combined dataset, we identified a total of 64 rotations in 12 sources, 39 of which are newly identified rotations. We confirm the trend of lower polarization degree during periods of polarization angle rotations for the whole sample found in previous works. However, looking at the individual sources, we identified cases where the rotation and non-rotation polarization degree distributions are indistinguishable, providing further evidence for the multiple emission mechanism hypothesis.

Cone search capability for table J/A+A/710/L33/sources (List of studied sources)