The milliarcsecond-scale jet of PKS 0735+178 during quiescence

Abstract

We present polarimetric 5 GHz to 43 GHz VLBI observations of the BL Lacertae object PKS 0735+178, spanning March 1996 to May 2000. Comparison with previous and later observations suggests that the overall kinematic and structural properties of the jet are greatly influenced by its activity. Time intervals of enhanced activity, as reported before 1993 and after 2000 by other studies, are followed by highly superluminal motion along a rectilinear jet. In contrast the less active state in which we performed our observations, shows subluminal or slow superluminal jet features propagating through a twisted jet with two sharp bends of about 90 deg. within the innermost three-milliarcsecond jet structure. Proper motion estimates from the data presented here allow us to constrain the jet viewing angle to values < 9 deg., and the bulk Lorentz factor to be between 2 and 4.

11 pages, 12 figures. Accepted for publication in A&A

References in corpus (1)

• Sub-milliarcsecond Imaging of Quasars and Active Galactic Nuclei III. Kinematics of Parsec-Scale Radio Jets

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• Radio Circular Polarization Produced in Helical Magnetic Fields in Eight Active Galactic Nuclei
• Ten-year optical monitoring of PKS 0735+178: historical comparison, multiband behaviour and variability timescales
• Multi-wavelength variability study of the classical BL Lac object PKS 0735+178 on timescales ranging from decades to minutes
• Evidence of internal rotation and a helical magnetic field in the jet of the quasar NRAO150
• Ambilateral collimation study of the twin-jets in NGC1052
• The dynamics of the parsec-scale jet in the neutrino blazar PKS 0735+178