CO SLED and its evolution with redshift. Points have been shifted in the x-axis for clarity. The transition used for normalization is J_up = 3. Colors encode the redshift, from z = 0.5 to 3.0. In the upper panel, solid lines and shaded areas are the mean and 1σ deviation of the background SLED from the SIDES-Uchuu catalog. Points are obtained from Eq. (15) (and thus from the ratio of clustering power spectra) and the associated error bars from the dispersion over the 12 subfields of 9 deg². The lower panel shows the relative difference between the mean SLED from the catalog and the measurement from the cross-power spectra.