Comparison of major axis slices at 40-arcsec resolution, averaged over 40 arcsec in z and normalized to their peak values. The positive x-axis is to the east. The thick red curve shows the CO(J = 3–2) emission taken from Fig. 1 and the thin red flanking curves show the extent of its error bars (which are the dominant uncertainties in the figure). The steep fall-off around +200 and −250 arcsec is due to the moment-generating routine. The black curve is the λ 24-μm emission from Fig. 4(b), the medium grey curve represents the λ 160-μm emission from Fig. 4(c) and the light grey curve represents Hα from Fig. 4(a).