Overlay of the average emission in the CH₃CN(19–18) K = 2 line (white contours) and 3.6 cm free-free continuum emission (red contours; from GHLW) on a map of the first moment (i.e. velocity) of the same CH₃CN line. The velocity intervals used to calculate the mean emission and first moment are 25.9−38.0 km s^-1 for core A and 25.9−33.0 km s^-1 for core B. The dashed line is intended to stress that different color scales are used for the two cores to emphasize the velocity gradients. The white contour levels range from 80 to 656 mJy/beam in steps of 96 mJy/beam. The crosses mark the positions of the 350 GHz continuum peaks. The ellipse in the bottom right indicates the synthesized beam.