Color–color selection diagrams in the different regions observed in this work. Upper panels: J₁₂₅ − H₁₆₀ vs. I − J₁₂₅ diagram for the UDS field (left) and the COSMOS field (right). Bottom panels: Z₈₅₀ − Y₁₀₅ vs. Y₁₀₅ − J₁₂₅ diagram for the GOODS-South field (left) and the Z₈₅₀ − Y₀₉₅ vs. Y₀₉₅ − J₁₂₅ for the ERS area (right). The blue circles are the detected objects, and the red circles are the undetected ones. Blue and red triangles represent, respectively, confirmed and unconfirmed objects that were selected only by means of their photometric redshift. The solid lines are the color cuts representing the different criteria described in Sect. 2.