Channel map of once-Hanning-smoothed spectra in the direction of the patch. The velocity V_r, hel − 3800 km s⁻¹ is shown in the upper-left corner of each panel. The cross marks the ALMA field phase centre, and the ALMA smoothed 22 by 212 beam is shown in the panel in the upper-left. The contours are from 0 mJy beam⁻¹ (thick contour) in one σ step of a 1.4 mJy beam⁻¹. Magellan Clay telescope MagIC B band image of the patch is shown in the lower-right, where the contours at arbitrary levels follow the drop in the relative optical surface brightness.