A&A 425, 783-796 (2004)
Galaxy evolution in the environment of ABCG 209C. P. Haines1, A. Mercurio1, 2, P. Merluzzi1, F. La Barbera1, M. Massarotti1, G. Busarello1 and M. Girardi2
1 Osservatorio Astronomico di Capodimonte, v. Moiariello 16, 80131 Napoli, Italy
2 Departimemto di Astronomia, Università degli Studi di Trieste, v. Tiepolo 11, 34100 Trieste, Italy
(Received 10 December 2003 / Accepted 19 May 2004)
We examine the environmental effects on the photometric properties of galaxies for the rich galaxy cluster ABCG 209 at z=0.209. We use archive CFHT optical imaging of a field centred on the cluster to produce a galaxy sample complete to B=25.0 and R=24.5. Both the composite and red sequence galaxy luminosity functions are found to be dependent on the local galaxy surface density, their faint-end slopes becoming shallower with increasing density. We explain this as a combination of the morphology-density relation, and dwarf galaxies being cannibalised and/or disrupted by the cD galaxy and the ICM in the cluster core. The B-R colour of the red sequence itself appears 0.02 mag redder for the highest-density regions, indicative of their stellar populations being marginally ( < 5%) older or ( < 20%) more metal-rich. This may be due to the galaxies themselves forming earliest in the rarest overdensities marked by rich clusters, or their star-formation being suppressed earliest by the ICM.
Key words: galaxies: clusters: individual: Abell 209 -- galaxies: luminosity function, mass fuction -- galaxies: evolution
© ESO 2004