Figure 2: Faint X-ray sources number counts in the 0.5–2 keV band and in four redshift ranges. Blue points are from X-ray detections at the position of ERS and GOODS-MUSIC galaxies [9]; green points are from Chandra-COSMOS [23]; red points are from XMM-COSMOS [24]. Circles = sources, squares = sources, triangles = , and star = sources. Diamond = Treister et al. determination [18]. The upper limit in the lower right panel is from Table 1. The thin solid curves are model number counts based on the best fit high- luminosity functions presented in [9].