The twisted parsec-scale structure of 0735+178

Abstract

We present two epoch polarimetric images of the BL Lac object 0735+178 obtained with the Very Long Baseline Array at 22 and 43 GHz. These images provide the highest resolution observations of this source to date, and show a twisted jet with two sharp apparent bends of 90 deg. within two milliarcseconds of the core. The magnetic field appears to smoothly follow one of the bends in the jet, suggesting that this structure may be the result of a precessing nozzle in the jet of 0735+178. Proper motion information is not conclusive as to whether the twisted geometry is the result of knots moving ballistically or following the direction of the jet axis.