Selection of the LBGs in the color-color diagram. The small gray dots are the sample of objects detected in the COSMOS field, which have magnitudes (V_J< 26.5 and i⁺< 26.1), and photo-z calculated from Ilbert et al. (2009, version 2.0). The pink dots are our sample selected within the limits of Eq. (1) (black lines), with photometric redshift between 2.5 and 3.5 and log(L_FUV[L_⊙]) > 10.2. The yellow dots are the stars identified by Ilbert et al. (2009, version 2.0). The diamonds correspond to the objects with spectroscopic redshift identify in the range 2.5 <z_spec< 3.5, color-coded red to blue as a function of their z_spec. The black lines correspond to the expected colors in redshift evolution (small dots, 0.2 ≤ z ≤ 2.5; large dots, 2.5 ≤ z ≤ 3.5) for three fiducial star-forming galaxies (see Sect. 3.3.1) with E(B − V) = 0,0.2, and 0.4. The panel inserted in the top right corner shows the probability of finding an object in the redshift range 2.5 ≤ z ≤ 3.5 for our selection. The blue and red lines are the probability of finding an object with a good photo-z or spectrocopic redshift (available within the COSMOS collaboration), respectively. The back line is the probability of finding an object with a spectroscopic redshift after selecting the objects with photo-z in the range 2.5 ≤ z ≤ 3.5 as we did in our sample selection (which corresponds to our redshift probability as a function of redshift).