Selection of CHeB candidates and their spatial distribution. Panel a: a rough CMD selection of CHeB candidates (blue dots) in the full field of 5 × 5 sq. deg. The PM-selected sample in the same field is plotted in gray dots. Panel b: the spatial distribution of the rough CHeB candidates, with histograms of counts projection on each axis for showing the significant concentration of the CHeB candidates at the Sculptor’s center. Panel c shows only the CHeB candidates that are selected by their locations in the CMD, spatial location within the elliptical radius of 1.1 deg. The red dashed line in both panels a and c is the CHeB selection condition (see Figure 3 and Sect. 3.3.1).