Map of the line velocity (moment 1) of CH₃CN K = 2 toward core A. Contour levels are the same as in Fig. 8. The white cross marks the position of the dust emission peak of core A. The dashed white line indicates the direction of the velocity gradient estimated as explained in Sect. 4.3. The dashed black line indicates the direction of the IR bipolar nebula (see Fig. 1). Red circles and magenta stars indicate the positions of H₂O and OH masers, respectively (Forster & Caswell 1999), and cyan triangles those of Class II 6.7 GHz CH₃OH masers (Cyganowski et al. 2009).