Left: contour map obtained by averaging the emission over the SiO(5–4) line from 4.0 to 39.1 km s^-1, overlaid on the map (grey scale) of the 1.4 mm continuum emission in G17.64. Contour levels range from 2.8 to 19.8 in steps of 3.4 mJy/beam. The synthesized beam is shown in the bottom right. Right: same as left panel, overlaid on the first moment map of the CH₃CN(12–11) K = 2 line. The dashed line indicates the direction of the axis of the ¹²CO outflow detected by Kastner et al. (1994).