Left panel: modified version of Fig. 3(b) of Shinnaga et al. (2012). The white box indicates the position of the right panel. The black bars represent the magnetic field direction determined from the polarized dust emission at 350 μm, whose continuum emission is in the background. Right panel: CH₃OH (triangles), OH (squares) (Edris et al. 2005), and H₂O (octagons) masers in IRAS 20126+4104. The gold asterisk represents the B0.5 protostar ( and , MCR11), while the dotted line represents the Keplerian disk of ~1000 au (PA_disk = 53° ± 7°, Cesaroni et al. 2005). The red and blue lines indicate the red- and blue-shifted lobes of the jet, respectively, with a PA_jet = 115° and an opening angle of 9° (MCR11). The thick green segments represent the magnetic field direction determined from the polarized CH₃OH and H₂O maser emissions. The green dashed segments represent the magnetic field direction determined from the linearly polarized emission of OH masers (Edris et al. 2005). The foreground Faraday rotation at 1.6-GHz is probably not negligible and needs to be taken into account when interpreting the image (see Sect. 5.2).