Fractional polarization, m, and EVPA of the C3*/P3* component, evaluated along concentric circular sections (see Fig. 5). The dark red line marks the average values across all range of radii considered, while the red shaded area represents the corresponding standard deviation. The black dotted line shows the EVPA of a purely radial polarization field, while the black dashed line shows the EVPA of a purely tangent polarization field. The gray shaded areas indicate the angles excluded from consideration because they coincide with regions below the noise threshold.