Expected redshift and colors distribution of WEAVE-StePS galaxies. Left panel: redshift distribution of a magnitude-limited sample of galaxies down to I_AB ∼ 20.5. The y-axis shows the expected surface density of galaxies per square degree and per 0.1 redshift interval. The mean values (thick line) and their field-to-field variance (shaded region) were obtained in random positions within the CFHTLS-W1 and CFHTLS-W4 photometric catalogues (Ilbert et al. 2006; Hudelot et al. 2012). These numbers were obtained by removing all regions masked because of lower-quality photometry. Right panel: expected two-colour distribution of our target sample on the rest-frame colour-colour (NUV − r) and (r − J) plane, as obtained using the WEAVE-StePS sample definition and the UltraVISTA catalogue in the COSMOS field (McCracken et al. 2012; Ilbert et al. 2013). This colour-colour plot is an efficient way to distinguish between quiescent and star-forming galaxies, avoiding a mix between dusty star-forming galaxies and quiescent galaxies, as extinction moves star-forming galaxies along a diagonal direction parallel to the slanted line in the plot (see Ilbert et al. 2010, for more details).