Same as Fig. 7, but with the different regions selected for background decontamination highlighted. The circles centred on the five bright galaxies represent their 5 R_e radius (R_e, GC), which corresponds to 2.7′ in the case of NGC 5018. The 10 small black circles, each with a radius of 2.7′, are the regions selected to collectively represent the random background. The large black annulus (with inner and outer radii of 26′ and 29′, respectively) represents the annular background. The red dashed ellipse indicates the elliptical over-density region, with major and minor axes of 50.4′ and 25.2′, respectively. See text for details.