Distribution of composite models in the u-W3, W1-W2 color plot. The models are created with X-CIGALE for an AGN type 1 and a host galaxy from z = 0 to z = 2.5. Top panel: no obscuration by polar dust is considered. The relative contribution of both components defined by the fraction of the dust luminosity coming from the AGN is color coded. Bottom panel: polar dust obscuration is added. Models generated with the SMC (resp., G04) extinction curve are plotted as red (resp., green). The SMC extinction curve leads to a larger reddening of the u-W3 color. All magnitudes are in AB units and the line boundary defined by Hickox et al. (2017) to identify obscured quasars is modified accordingly (u − W3 = 1.4 × (W1 − W2) + 4.1). The number of G04 models is reduced by a factor of 2 on the figure for a better visibility for both distributions.