The Faraday rotation of NRAO150

As a complementary measurement, we determined the behavior of polarization as a function of observed frequency. The polarization from NRAO 150 only comes from the core region, with a peak polarization intensity occurring at 24GHz. Across the core region of NRAO 150, we see clear gradients in Faraday rotation and EVPA0 values that are aligned with the direction of the jet curving around the core region.

We find that for the majority of the polarized region the polarization fraction is greater at higher frequencies, with intrinsic polarization fractions in the core ~=3%. The Faraday rotation gradients and circular patterns in EVPA0 offer strong evidence to support the presence of a helical+toroidal magnetic field. Furthermore, the presence of low intrinsic polarization fractions indicate that the polarized emission and, hence, the helical+toroidal magnetic field, is present within the innermost jet.