The red-sequence of 72 WINGS local galaxy clusters
/ Authors
T. Valentinuzzi, B. Poggianti, G. Fasano, M. D’Onofrio, Alessia Moretti, M. Ramella, A. Biviano, J. Fritz, J. Varela, D. Bettoni
and 7 more authors
B. Vulcani, M. Moles, W. Couch, A. Dressler, P. Kjaergaard, A. Omizzolo, A. Cava
/ Abstract
The Niels Bohr Institute, Juliane Maries Vej 30, 2100 Copenhagen, DenmarkSeptember 20, 2011ABSTRACTWe study the color-magnitude red sequence and blue fractionof 72 X-ray selected galaxy clusters atz = 0.04−0.07 from the WINGSsurvey, searching for correlations between the characteristics of the red sequence and the environment. We consider the slope andscatter of the red sequence, the number ratio of red luminous-to-faint galaxies, the blue fraction and the fractions of ellipticals, S0sand spirals that compose the red sequence. None of these quantities correlate with the cluster velocity dispersion, X-ray luminosity,number of cluster substructures, BCG prevalence over next brightest galaxies and spatial concentration of ellipticals. Instead, theproperties of the red sequence depend strongly on local galaxy density. Higher density regions have a lower RS scatter, a higherluminous-to-faint ratio, a lower blue fraction, and a lowerspiral fraction on the RS. Our results highlight the prominent effect of thelocal density in setting the epoch when galaxies become passive and join the red sequence, as opposed to the mass of the galaxy hoststructure.Key words. Surveys – Galaxies : Clusters : General – Galaxies: evolutio n – Galaxies: star formation – Galaxies: structure
Journal: Astronomy and Astrophysics