Close-up view of the 22 GHz H₂O maser features detected around the radio source VLA 1 (left panel) and VLA 2 (right panel). The reference position is and (see Sect. 2). The octagonal symbols are the identified maser features in the present work scaled logarithmically according to their peak flux density (Tables A.1 and A.2). The linear polarization vectors, scaled logarithmically according to polarization fraction P_l, are overplotted. In the bottom-right corner of both panels the error-weighted orientation of the magnetic field (Φ_B, see Sect. 3) is also reported; the two dashed segments indicate the uncertainties. The ellipse drawn in the right panel is the result of the best fit of the H₂O masers detected in the present work (epoch 2012.54). Its parameters are listed in Table 1. The estimated values of the magnetic field strength are also shown in both panels next to the corresponding H₂O maser.