(a) Sharpened version of the 1.3 mm continuum map I_{1.3 mm} shown in Figure 1(a), using an unsharp-masking procedure to enhance the fine structure of the continuum ring. The image is deprojected to show a face-on view. (b) Surface brightness profiles from the original I_{1.3 mm} image. The blue solid line corresponds to the azimuthally averaged radial profile, while the family of thin gray curves correspond to profiles extracted from 3.°6 wedges covering the full azimuthal range. The solid red curve shows the azimuthally averaged profile of the sharpened imaged shown in panel (a). The shaded area around the profile corresponds to the dispersion around the mean. (c) Polar deprojection of I_{1.3 mm}, zoomed on the continuum ring. The circle in (a) and (c) shows the approximate location of the Doppler flip seen in ¹²CO gas.