Pan-STARRS aperture-color vs. Kron-like magnitude diagrams r − i vs. r and g − r vs. r in lower and upper panels, respectively. All member galaxies are shown with the exception of two very faint galaxies for which PS1 magnitudes are not available. The full circles indicate data obtained from PS1 mean data and open circles those available only as stacked data. The large green squares indicate BGG1 and BGG2. The blue dashed lines show the color-magnitude relations obtained for the member galaxies. The red dotted lines show the relations taken from the literature (see Sect. 7).