HST/ACS image (F814W filter) with superimposed K-band contours from CFHT (blue, arbitrary levels chosen to trace the whole K-band emission). Black contours represent CO(3−2) emission from the integrated map in the channels corresponding to the “systemic” peak of the line (same levels as in right panel of Fig. 1; starting from 1 sigma). The black cross (with associated ellipse) marks the line centroid. The image is about 10′′ across. The beam size is 4.5′′ × 3.4′′, with an angle of 38 degrees.