Galaxy cluster searches based on photometric redshifts in the four
  CFHTLS Wide fields
  We have developed a method for detecting clusters in large imaging surveys,
based on the detection of structures in galaxy density maps made in slices of
photometric redshifts. This method was first applied to the Canada France
Hawaii Telescope Legacy Survey (CFHTLS) Deep 1 field by Mazure et al. (2007),
then to all the Deep and Wide CFHTLS fields available in the T0004 data release
by Adami et al. (2010). The validity of the cluster detection rate was
estimated by applying the same procedure to galaxies from the Millennium
simulation. Here we analyse with the same method the full CFHTLS Wide survey,
based on the T0006 data release. In a total area of 154 deg2, we have detected
4061 candidate clusters at 3sigma or above (6802 at 2sigma and above), in the
redshift range 0.1<=z<=1.15, with estimated mean masses between 1.3 10^14 and
12.6 10^14 M_solar. This catalogue of candidate clusters will be available
online via VizieR. We compare our detections with those made in various CFHTLS
analyses with other methods. By stacking a subsample of clusters, we show that
this subsample has typical cluster characteristics (colour-magnitude relation,
galaxy luminosity function). We also confirm that the cluster-cluster
correlation function is comparable to that obtained for other cluster surveys
and analyze large scale filamentary galaxy distributions. We have increased the
number of known optical high redshift cluster candidates by a large factor, an
important step towards obtaining reliable cluster counts to measure
cosmological parameters. The clusters that we detect behave as expected for a
sample of clusters fed by filaments at the intersection of which they are
located.
