Enhanced versions of the major axis frame of Fig. 9. (a) Blow-up of the nuclear region emphasizing the brightest emission with contours at 0.2, 0.25, 0.3, 0.33, 0.35 and 0.4 K. The x-axis is centred on the IR centre (Table 1). The cross marks the location of the modelled ring centre in x (Table 3) and V_sys (from the total global profile of Fig. 8), with the cross size delineating their respective error bars. The green line shows the nuclear gradient (see Section 3.6.1). (b) Here, the major axis has been smoothed spatially with a Gaussian of FWHM = 11 arcsec to emphasize the fainter emission. Contours are at 0.028 (2σ), 0.035, 0.050 and 0.074 K. Features have been labelled as in Fig. 9. Inset: CO(J = 1–0) major axis emission from the original data of Rand (2000a) rotated and smoothed as in the main figure; contours have been arbitrarily set.