2000A&A...354...55R

We have studied the parsec-scale structure of the quasar 3C 345 at λλ1.3, 2, 3.6, and 6cm, using total intensity and linear polarization images from 3 epochs of VLBA observations made in 1995.84, 1996.41, and 1996.81. The images show an unresolved ``core" and a radio jet extending over distances up to 25milliarcseconds. At 1.3 and 2cm, images of the linearly polarized emission reveal an alignment of the electric vector with the extremely curved inner section of the jet. At 6cm, the jet shows strong fractional polarization (m∼15%), with the electric vector being oriented perpendicular to the jet. This is consistent with the existence of a transition from the shock-dominated to the plasma interaction-dominated emission regimes in the jet, occurring at a distance of ∼1.5milliarcseconds from the ``core".