Color Bimodality in Galaxy Clusters to z = 1.
Abstract
We present the evolution of the color bimodality of galaxy clusters from z = 0.45 to z = 0.95 using a homogeneously selected sample of ∼ 2000 clusters with B{gc, red} > 300 (corresponding to Abell Richness Class > 0; comoving density < 10-5 h3 Mpc-3) drawn from the 92 deg2 Red-Sequence Cluster Survey (RCS). The red fraction of galaxies decreases as a function of redshift for all cluster-centric radii, consistent with the Butcher-Oemler (1978) effect. The color-radius relation is also well established at all redshifts, with the red fraction decreasing toward the cluster outskirts. We detected a more rapid rate of redshift evolution in the red fraction at the cluster core compared to the cluster outskirts, suggesting that the higher galaxy infall rate at earlier times contributes significantly to the Butcher-Oemler effect seen in these clusters. This work is partially funded by NSF AST 0206154 and NASA.
- Publication:
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American Astronomical Society Meeting Abstracts
- Pub Date:
- December 2005
- Bibcode:
- 2005AAS...20719005L