Get access

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


  • Mauri J. Valtonen,

    Corresponding author
    1. Helsinki Institute of Physics, University of Helsinki, PO Box 64, FIN-00014 Helsinki, Finland
    Search for more papers by this author
  • Kaj Wiik

    1. Tuorla Observatory, Department of Physics and Astronomy, University of Turku, Väisäläntie 20, FI-21500 Piikkiö, Finland
    Search for more papers by this author



We study the variation of the optical polarization angle in the blazar OJ287 and compare it with the precessing binary black hole model with a ‘live’ accretion disc. First, a model of the variation of the jet direction is calculated, and the main parameters of the model are fixed by the long-term optical brightness evolution. Then this model is compared with the variation of the parsec-scale radio jet position angle in the sky. Finally, the variation of the polarization angle is calculated using the same model, but using a magnetic field 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 almost parallel to the jet axis. This may imply a steady magnetic field geometry, such as a large-scale helical field.

Get access to the full text of this article