NH₃(1, 1) intensity (grey contours) and radial velocity (color map) structure in the source Do279P12. The velocity field is shown after subtracting the mean radial velocity ⟨ V_LSR ⟩  = 8.099 km s^-1. The contour levels are the same as in Fig. 4a. Panels A) and B) represent the velocity maps for the components A and B in the NH₃ profile, respectively (see Fig. B.4). The white crosses mark offsets where the splitting of the NH₃ profiles is detected. The mean radial velocities of the components A and B are ⟨ V_A ⟩  = 7.27 ± 0.11 km s^-1 and ⟨ V_B ⟩  = 8.54 ± 0.08 km s^-1. In panel B), the intensity peaks are labeled as in Table 1.