Plot of the LS g − z versus g − W₁ galaxy colours for the candidates remaining after the base cuts (orange), compared to contours from confirmed and candidate lens galaxies (blue), and QSOs detected by WISE (green). The data was acquired by cross-matching the AGN and lens catalogues with LS (Duncan 2022). The dashed lines indicate the colour cuts which were devised to select likely elliptical and lens galaxies, shown in Table 2. A single redshift bin of 0.2 < z < 0.3 is shown for clarity. The two star markers show the lens galaxy colours for iPTF16geu (grey) and SN Zwicky (black), which had lens redshifts of 0.216 and 0.226, respectively. For SN Zwicky, the g − z versus g − W₁ colours from Pan-STARRS are shown instead, because the lens galaxy was not present in the LS catalogue).