Root mean square velocity dispersion (second moment) maps of most important lines covered in the narrow-band receiver for the observations in the ABD configuration for W3(H₂O) (top panel) and W3(OH) (bottom panel). The solid contours correspond to the dust continuum and start at and increase by 6σ (1σ = 3.2 mJy beam⁻¹). The sizeof the synthesised beam is shown in the bottom left of each panel. The map of CH₃CN (12₅−11₅) may not be accurate because it is blended with other lines.