Lower panel: spatial distribution of all galaxies considered group members (blue and red sequence, see Sect. 3.2.2). Spectroscopically confirmed group members are denoted by dotted shapes. All objects are color-coded with respect to their B − R color, and the size of each galaxy is scaled to its luminosity by roughly L^0.03. Ellipticity and position angle are represented by its value at the half-light radius. The solid circle represents the area that is completely covered by our field of view (r = 229 kpc). The size of the dotted circle corresponds to the virial radius (r_vir = 310 kpc). The arrow in the southwest corner indicates that another spectroscopically confirmed cluster member lies outside the field of view. Upper panel: angular distribution of all galaxies shown in the lower panel within the solid circle. The 0 deg position is north in the lower panel and the angle grows clockwise. The errors in this plot are Poissonian.