Intensity-weighted peak velocity (first moment) map of CH₃CN (12₃−11₃) using only the A-array observations and masked out to show contributions from W3(H₂O) W (top panel) and W3(H₂O) E (bottom panel). The solid contours correspond to the 1.37 mm continuum in the A-array only observations and start at 6σ and increase in steps of 3σ (1σ = 2.5 mJy beam⁻¹). The dashedlines correspond to the cuts made for the PV plots (Fig. 10). The blue and red arrows show the directions of bipolar molecular outflows (Fig. 6). A scale bar and the synthesised beam (0.′′ 39×0.′′28, PA = 88°) are shown in the bottom. The velocity ranges are different for the two cores.