Maps of the blue- (blue contours) and red-shifted (red contours) SiO (8–7) emission overlaid on the CH₃CN (19–18) K = 2 velocity field (color scale) towards core A. The maps have been obtained by averaging the emission over the velocity intervals 25.2–28.6 km s^-1 and 40.8–57.7 km s^-1. Contour levels range from 0.05 to 0.27 in steps of 0.05 Jy beam^-1 km s^-1 and from 0.15 to 1.19 in steps of 0.15 Jy beam^-1 km s^-1, for blue and red-shifted emission, respectively. Black contours are a map of the 3.6 cm continuum emission (Gibb et al. 2003), with levels from 0.039 to 0.533 in steps of 0.026 mJy beam^-1. The dashed line shows the direction of a possible jet associated with core A.