Top panel: r-band AB magnitude as a function of z for the extended sample. Red circles represents the galaxies with m_r> 22.2 excluded from the sample because of incompleteness. Bottom panel: normalized histograms of the m_r − m₂₅₀ index for the main (black solid line) and extended (red dashed line) sample. The vertical blue dotted line shows the color limit considering both r-band and 250 μm detection limits.