Left: location of the LBGs of Steidel et al. (2003) with confirmed spectroscopic redshifts (red dots) in the color–color diagram employed to select the LBGs studied in this work. The light grey shaded zone represents our selection window for LBGs at z ~ 3 (see Eq. (A.1)). Black open squares are the complete sample of galaxies in the Capak et al. (2004) photometric catalog. For comparison, we also show the selection window for LBGs of Pentericci et al. (2010) with a dark grey shaded zone. Right: photometric redshift accuracy for our LBGs at z ~ 3. Only galaxies with confirmed spectroscopic redshift via emission lines (light green symbols) or absorption lines (dark green symbols) in Steidel et al. (2003) are included. The PACS-detected LBG spectroscopically confirmed to be at z = 2.929 in Steidel et al. (2003) is indicated with an orange dot. The PACS-detected LBG spectroscopically confirmed to be at z = 2.975 in Popesso et al. (2009) and Balestra et al. (2010) is presented with a red dot.