Jet Kinematics of AGNs at High Radio Frequencies

Jorstad, S.G.; Marscher, A.P.; Lister, M.; Stirling, A.M.; Cawthorne, T.V.; Gomez, J-L.; Gear, W.K.; Stevens, J. A.; Robson, E.I.; Smith, P.S.; Forster, J.R.

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Author

Jorstad, S.G.

Marscher, A.P.

Lister, M.

Stirling, A.M.

Cawthorne, T.V.

Gomez, J-L.

Gear, W.K.

Stevens, J. A.

Robson, E.I.

Smith, P.S.

Forster, J.R.

Abstract

We have completed a 3 yr program of polarization monitoring of 15 active galactic nuclei with the Very Long Baseline Array at 7 mm wavelength. At some epochs the images are accompanied by nearly simultaneous polarization measurements at 3 mm, 1.35/0.85 mm, and optical wavelengths. We determine apparent velocities in the jets of all sources in the sample. We suggest a new method to estimate Doppler factor of the jet components based on their VLBI properties. This allows us to derive the Lorentz factors and viewing angles of superluminal knots and opening angles of the jets.