Photometric validation of a model independent procedure to extract galaxy clusters

By means of CCD photometry in three bands (Gunn g, r, i) we investigate the existence of 12 candidate clusters extracted via a model independent peak finding algorithm (Puddu et al. 2000) from DPOSS data. The derived color-ma gnitude diagrams allow us to confirm the physical nature of 9 of the cluste r candidates, and to estimate their photometric redshifts. Of the other can didates, one is a fortuitous detection of a true cluster at z similar to 0. 4, one is a false detection and the last is undecidable on the basis of the available data. The accuracy of the photometric redshifts is tested on an additional sample of 8 clusters with known spectroscopic redshifts. Photome tric redshifts turn out to be accurate within z similar to 0.01 (interquart ile range).