Median simulated magnitudes of the faint mock sample in the Euclid, Rubin, and Spitzer filters. Light brown circles represent stable intermediate-z galaxies, red stars z > 6 contaminants, and blue diamonds true z > 6 galaxies. For each population, the dotted lines indicate the 16th and 84th percentiles. The 2σ flux limits are shown with green bars. The selection of intermediate-z, contaminants, and z > 6 galaxies from the faint mock sample is based on Euclid+Rubin+Spitzer data. The median magnitudes for z > 6 galaxies in the Rubin u and g bands and for contaminants in the Rubin u band are equal to −99 (no intrinsic flux) and therefore omitted from this figure.