[Previous] | [Session 92] | [Next]
V.I. Pariev (University of Rochester; Lebedev Physical Institute), M. Lyutikov (McGill University; CITA)
If the emitting volume of plasma moves relativistically, as it is the case for almost all extragalactic and galactic jets, Lorentz transformations of electromagnetic field and the direction of the propagation of the photon result in that the electric vector of the wave is no longer orthogonal to the projection of the magnetic field on the sky. This changes the interpretation of the astronomical polarization observations. We calculate polarization properties of optically thin synchrotron radiation emitted by a steady-state cylindrical relativistically moving jet carrying large scale helical magnetic fields. Calculations are done for different structures of force-free jets. For unresolved jets, the position angle of the electric vector of linear polarization has a bimodal distribution being oriented either along or perpendicular to the jet axis. In order to have polarization along the axis the intrinsic toroidal magnetic field (in the frame of the jet) should be of the order of the poloidal field; in this case the toroidal magnetic field in the laboratory frame is much larger than the polodial field. For resolved jets we find that the central parts of the jet are polarized along the jet axis,while the outer parts - perpendicular to it, in accordance with observations. Our calculations are supportive for the presence of a large-scale spiral magnetic fields in AGN jets.
The author(s) of this abstract have provided an email address for comments about the abstract: vpariev@pas.rochester.edu
[Previous] | [Session 92] | [Next]
Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.