Galaxy clusters in the CFHTLS

We apply a matched-filter cluster detection algorithm to the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) i-band data for the Deep-1, Deep-2, Deep-3 and Deep-4 fields covering a total of 4 square degrees. To test the implemented procedure we carry out simulations for assessing the frequency of noise peaks as well as estimate the recovery efficiency. We estimate that up to $z\sim0.7$ the catalogue is essentially complete for clusters of richness class $R \ga 1$. The recovered redshifts are in general overestimated by $\Delta z=0.1$ with a scatter of ${\sigma}_{\Delta z}\sim0.1$, except at redshifts $z \ga 1$ where the estimated redshifts are systematically underestimated. The constructed cluster candidate catalogue contains 162 detections over an effective area of 3.112 square degrees corresponding to a density of ~52.1 per square degree. The median estimated redshift of the candidates is $z=0.6$. The estimated noise frequency is $16.9\pm5.4$ detections per square degree. From visual inspection we identify systems that show a clear concentration of galaxies with similar colour. These systems have a density of ~20 per square degree