Parsec-scale polarization of the jet in quasar 4C71.07

Very long-baseline interferometry (VLBI) observations of the quasar 4C 71.0 7 (0836+710) at frequencies of 5 and 8.4 GHz at two epochs are used to inve stigate apparent misalignments between the magnetic field and jet direction found in this source. The observed polarization angles are not consistent with Faraday rotation of synchrotron radiation from an aligned magnetic fie ld. Internal Faraday rotation in a uniform spherical source is also ruled o ut by the observations, and while the misalignments could result from inter nal Faraday rotation in a non-uniform source, no strong signatures of this effect were found. The jet shows two distinct kinks at which the ridge-line changes direction and then reverts to its original direction. The magnetic field in these regions is parallel to the jet, and remains so as the jet b ends. It seems likely that the largest remaining misalignment is associated with another such kink that is unresolved by these observations. The perce ntage polarization decreases near the bright knots, consistent with enhance ment in brightness by compressions in the plane normal to the jet axis. The inferred rotation measure is low (less than or equal to 100 rad m(-2)) thr oughout the jet, as for other quasars. However near the core, the polarizat ion position angles suggest a rotation measure that appears to be uncharact eristically low by comparison with other quasars.