2006MNRAS.368.1500T

We present Very Long Baseline Array (VLBA) observations of the nucleus of NGC1275, the central, dominant galaxy in the Perseus cluster of galaxies. These are the first observations to resolve the linearly polarized emission from 3C84, and from them we determine a Faraday rotation measure (RM) ranging from 6500 to 7500rad/m2 across the tip of the bright southern jet component. At 22GHz some polarization is also detected from the central pc of 3C84, indicating the presence of even more extreme RMs that depolarize the core at lower frequencies. The nature of the Faraday screen is most consistent with being produced by magnetic fields associated with the optical filaments of ionized gas in the Perseus cluster.