HIPASS and ATCA Hi maps are represented by contours overlaid on the DSS red optical image with the residual emission between them. The contours of the HIPASS and the high-resolution ATCA images are shown in light- and dark-gray, respectively. The levels are the same as in Figs. 1 and 4. The smoothed and regridded ATCA image is shown in white contours at the same levels as the HIPASS data. The residual emissions of (1, 2, 3, 5) ×σ are shown in green, cyan, light-blue, and blue, respectively, which are comparable to (2.5, 5, 7.5, 12) ×σ of the HIPASS data.