Left: position–velocity diagram along the major axis of the disk model of Fig. 4. Contours show our best fit rotating disk model at 1%, 5%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 95% of the peak flux. Centre: rotation curve extracted along the major axis with our best-fit model overplotted as a dashed line. Right: the variation in velocity dispersion as a function of radius in the disk. We estimate a typical V_rot/σ_int ~ 3.1 in the disk, showing that it is relatively turbulent. The rise towards the centre in the observed dispersion is an artifact resulting from the limited spatial resolution of the data. The synthesised beam size is shown as a horizontal black bar in the top left corner of the central and right panels.