Left panel: NGVS g-band image in grayscale. The green ellipse arcs mark the shells. Middle panel: Slit profile of original g-band image (solid red curve) and unsharp-masked image (solid purple curve). The g−i color slit-profile measured from the smoothed g and i images by ADAPTSMOOTH (Zibetti et al. 2009) is plotted with a dashed blue line. The green vertical lines mark the radii of the stellar shells. Right panel: Unsharp-masked g-band image. The red (left panel) and purple (right panel) rectangular regions indicate the area used to extract the slit profiles shown in middle panel.