Color–color diagram of W1 − W2 against W2 − W3 comparing the distributions of a mock (black dots) and a real star-forming galaxies from SDSS (red contours). We see very good agreement between the two galaxy samples. Also, both samples occupy the area well bellow the W1 − W2 = 0.8 (dashed black line) demarcation line defined by Stern et al. (2012) between the AGN and non-AGN galaxies and the AGN selection wedge (solid black lines) defined by Mateos et al. (2012). We also show a sample of photometrically selected passive galaxies (green contours) for comparison. Photometric bands from the WISE survey are shown. The mock data were artificially augmented with noise to achieve an S/N of 10 to match to the selection criteria for the WISE bands. Contour levels denote the 10th, 25th, 50th, 75th, and 90th percentiles for each population.