Optical polarization angle and VLBI jet direction in the binary black hole model of OJ287

摘要

We study the variation of the optical polarization angle in the blazar OJ287and compare it with the precessing binary black hole model with a 'live'accretion disk. First, a model of the variation of the jet direction iscalculated, and the main parameters of the model are fixed by the long termoptical brightness evolution. Then this model is compared with the variation ofthe parsec scale radio jet position angle in the sky. Finally, the variation ofthe polarization angle is calculated using the same model, but using a magneticfield configuration which is at a constant angle relative to the optical jet.It is found that the model fits the data reasonably well if the field is almostparallel to the jet axis. This may imply a steady magnetic field geometry, suchas a large-scale helical field.