Surface brightness profile along the bridge. Measurements are made in boxes parallel to the main axis, in the g (green) and r (red) bands. The green and red areas at the bottom indicate the limiting surface brightness computed from the maps elaborated by Román et al. (in prep.), averaged inside the same boxes. The position of the bridge is marked with dashed vertical lines, and the directions towards the core of Coma and the NGC 4839 group are indicated with arrows.