Total intensity and polarized emission of the parsec - scale jet in 3 C 345

We have studied the parsec-scale structure of The images show an unresolved " core " and a radio jet extending over distances up to 25 milliarcseconds. At 1.3 and 2 cm, images of the linearly polarized emission reveal an alignment of the electric vector with the extremely curved inner section of the jet. At 6 cm, 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 ∼1.5 milliarcseconds from the " core " .