Arcs statistics as a probe of galaxy evolution

Number counts and redshift distribution of gravitational arcs are computed in the field of massive clusters of galaxies to probe the universe at high redshift. Using an accurate modelling for the cluster mass distribution and a model for the spectrophotometric evolution of galaxies, the redshift distribution of gravitational arclets is computed in the field of cluster Abell 2218 and in the Hubble Deep Field where a cluster is artificially located. Counts are very well reproduced in the B band but an important population appears at high redshift which is not seen in deep spectroscopic surveys. Unfortunately, the very high sensitivity of the counts with respect to the model for galaxy evolution and to the mass distribution prevents from estimating the cosmological parameters with arcs statistics. Future works have to concentrate on high redshift clusters and take advantage of objects with smaller distortions.