Stacks by EW(CIII]). Left to the right on top row: Stack A, Stack D. Middle row: Stack B. Bottom row: Stack C. In each panel, the green faint line is the stack spectrum with the ∼0.6 Å/pixel sampling, while the black one is with ∼1.2 Å/pixel. The blue line in the 1-σ error spectrum. The vertical lines mark known UV lines. Information about the number of galaxies, the mean redshift and the mean parameter are included in each panel.