Contours of the total HI image drawn on top of an optical g band image obtained with the LBT, both from Paper I. Contour levels are 5, 10 (black contours), 20 and 50 (white contours)  × 10¹⁹ cm^-2. Blue circles denote the stars with −0.4 < V − I < 0.0 and 23 < I < 25.5 while the cyan circles show the positions of the stars in the same color interval but with I < 23, as if Fig. 1).