Sensitivity of density maps for “Best” (upper panel) and “Worst” (lower panel) cases in the distance vs. surface brightness plane. The symbols are the same as in Fig. 8. In particular, light open circles are known dwarf galaxies in the LV, from McConnachie (2012). Central surface brightness values reported in the McConnachie (2012) catalogue were transformed into μ_V,h assuming exponential profiles, an acceptable approximation in the considered range of luminosity (Mateo 1998). We labelled six remarkable systems. The dashed line indicates the SDSS detection limit as a function of distance for resolved stellar systems from Koposov et al. (2008, their Table 3); the dotted line is the detection limit of the PAndAS survey (Ibata et al. 2007) in the surroundings of M 31, from Brasseur et al. (2011).