Maps of total intensity at 1420 MHz (left) and polarized intensity at 10.45 GHz (right). Intrinsic magnetic field vectors corrected for Faraday rotation are overlaid in white. The length of the vectors corresponds to the polarized intensity at 10.45 GHz. The black cross indicates the position of the pulsar J2229+6114. In the area of the "tongue," where we did not display the rotation measure in Fig. 6, an average RM calculated between the two possible ones determined in Fig. 5 was used to correct the observed polarization angle at 10.45 GHz for the Faraday rotation. The additional error in the intrinsic magnetic field angle introduced by this procedure is less than ±2°.