Studying magnetic fields in several parsec-scale AGN jets using Faraday Rotation

摘要

We present multi-frequency radio observations from the Very Long BaselineArray (VLBA) of selected AGN that seem to have a B-field structure with acentral "spine" of B-field orthogonal to the jet and a longitudinal B-fieldnear one or both edges of the jet. Two explanations for this structure havebeen discussed in the literature: shocks making the central orthogonal fieldcombined with a jet-medium interaction causing the longitudinal "sheath", orboth components produced by a helical jet magnetic field. One way toinvestigate this structure is to look for gradients in the Faraday Rotationacross the jet. We will discuss results for 0333+321, 1150+812 and 2037+511providing evidence for the latter picture.