Difference between the polarization angles at 1.3 mm and 3.1 mm. Polarization angle residuals (colors) between the 1.3 mm and 3.1 mm observations, superposed to the 3.1 mm dust continuum emission (contours). Contour levels are the same as in Fig. 1. The letters (A, B, C, D) show the position of four embedded continuum sources listed in Table 1. The hatched areas show the regions where |Δψ| > 45^o. The inset shows the distribution of the polarization angle residuals obtained considering the whole range of Δψ (green) and limited to |Δψ| ≤ 45^o (magenta). The solid lines show the corresponding Gaussian fits to the histograms whose mean value and standard deviation are −6.43^o ± 25.22° and −4.45^o ± 14.15°, respectively.