Top: combined CO(6−5) spectrum of NW + SE, extracted from data smoothed to the resolution of the CO(1−0) data. The red spectrum is the CO(1−0) emission from the same region, scaled up by a factor of 13. The red line is the model fit to the CO(1−0) spectrum (see EM15). The dark-grey area reveals the “high-excitation” residuals when subtracting the CO(1−0) model from the CO(6−5) profile. Bottom: total intensity plots of the velocity ranges where the blue and red wing dominate the CO(6−5) flux, as indicated by the dark-blue, blue and red bars. Contour levels: 2.8, 3.8, 4.8 σ, with σ = 0.064 Jy beam^-1 × km s^-1. The grey-scale image and thin black/white contours show the HST/WFPC2 image from EM15. The green circles show the location of the CO(6−5) peak emission from the total intensity image of Fig. 2, derived by fitting a point-source model to the NW and SE component in the image plane (the size of the circles represents the positional uncertainty of this model-fit).