Overlay of the bulk (top panel) and blue- and red-shifted emission (bottom panel) of the CH₃CN K = 3 line on the image of the H₂ 2.2 μm line emission obtained by C2013. The green points and arrows denote the H₂O maser spots and associated proper motions measured by Moscadelli et al. (2005). Contour levels in the top panel are the same as in Fig. 4, while in the bottom panel range from 15 to 225 in steps of 30 mJy/beam.