Composite source-plane reconstruction of JVAS B1938+666. Left: The colour map is the CO (1–0) surface density distribution, while the red and white contours indicate the rest-frame optical (Keck-AO) and radio emission, respectively, where the contour levels are set to 20, 40, 60, 80, and 95 per cent of the peak optical and radio intensity. Right: The intrinsic velocity field of JVAS B1938+666, where the black contours trace the CO (1–0) moment zero emission, which are set to 1, 20, 40, 60, 80, and 95 per cent of the moment zero peak.