r-z vs. z-k diagram for 67 out of 71 AGN candidates (larger dots) in our list, for which a stellarity index (ranging from 0 to 1 with decreasing extension of the source: see legend on the right of the plot) and color information are available after other COSMOS catalogs. The faint, smaller objects represent all the objects detected in the VST survey of the COSMOS field for which stellarity index and color information are available, and are shown as a reference population. The sources labeled by a cross are the AGNs whose nature has already been confirmed, while the triangles are for the eight SNe common to our catalog and to that by Cappellaro and collaborators, plus the four possible SNe by either catalog (2 out of these 12 sources are not in the plot because their k-band magnitude is missing in the catalog). The plot shows three new objects which, according to their stellar-like color and their position in the diagram, turn out to be QSO-like AGNs; they are marked by a box. K_s magnitudes are by McCracken et al. (2010).