SIMBAD references

This paper presents four color intermediate-band photometry of the cluster A 2218 carried out using the Wise Observatory 1m telescope. A 2218 is one of the richest clusters in the Abell catalogue, with richness class 4. We find that A 2218 has an unusually low fraction of blue galaxies for its redshift (z=0.171), and is populated mainly by E/S0 galaxies, while starburst systems are very scarce. The few starbursting galaxies present populate the faint end of the cluster luminosity function, close to the limiting magnitude of our observations. The difference between A 2218 and other clusters at similar redshifts is very remarkable, underlining the influence of cluster richness on the evolution of its member galaxies.