Faraday RM at high frequencies. (Top panel) 43−227 GHz rotation measure map with 86 GHz total intensity contours at increasing powers of 2, lowest contour 3.34 mJy beam⁻¹. Sticks denote linear polarization orientation at 86 GHz corrected for Faraday rotation. Numbers indicate locations where the EVPA(λ²) fits (bottom panel) are taken. Faraday rotation regression is shown by lines, and estimated values are given in rad m⁻¹.