Name of the Speaker(s): N.M.Shakhovskoy and Yu.S.Efimov
Institution: CRIMEAN ASTROPHYSICAL OBSERVATORY (Ukraine)
Title of the communication: Helical structure of magnetic fields in blazar's jets revealed by optical polarization observations.
Preliminary abstract (12 lines max.): In terms of blazars shock-jet model the long sets of polarization observations may reveal the type of magnetic field structure in jets. One types of structure is helical field. The best example of field this type give UBVRI polarization observations of OJ 287 obtained in Crimean Observatory at its strong outburst in 1994-95. These observations show the cyclic variations of observed position angles indicating the continuous clockwise rotation of polarization plane of variable source with the speed about 5 deg/day during 165 days. This is an evidence of the presence of the helical magnetic field in the jet. The others cases of sporadic cyclic variations of optical polarization in blazars we had found for OJ 287 in its quiescent state in 1975, April (with the same direction of rotation) and for PKS 0735+16 at the time of its strong outburst in 1977.