Upper array of four panels: r27 surface density maps for fields J (including Leo P), A, B, and C. Dots correspond to the sources used to compute the density maps. Surface density levels are expressed in units of σ_bkg above the background in different tones of grey, from the lightest (ρ ≥ 3.0σ_bkg to the darkest ρ ≥ 40.0σ_bkg, as illustrated by the vertical greyscale bar. Lower array of four panels: same for the r25 maps.