Properties of the Dwarf Galaxy Population in Galaxy Clusters - AstrophysicsReport as inadecuate

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Abstract: We present the observational properties of the dwarf galaxy population Mr >M*+1 corresponding to one of the largest samples of spectroscopicallyconfirmed galaxy cluster members reported in the literature. We have observedthat red dwarf galaxies u-r > 2.22 share the same cluster environment as thebrightest cluster members Mr < -21, but are not in dynamical equilibrium. Wecomputed the dwarf-to-giant ratio DGR using a spectroscopically selectedsample. The DGR was found to vary with clustercentric distance, essentially dueto the blue dwarf population u-r < 2.22. The u-r color of red dwarf galaxieswas independent of their environment and similar to the color of red isolateddwarfs. Blue dwarf galaxies located outside r200 show similar u-r colors tothose of the field population, while strong reddening was observed toward thecluster center. We also present evidence that the fraction of red to blue dwarfgalaxies in clusters is larger in the innermost cluster regions. We concludethat the present red dwarf population observed in the central regions of nearbygalaxy clusters could be related to the blue dwarf population observed inclusters at high redshift.

Author: R. Sánchez-Janssen, J. Alfonso L. Aguerri, C. Muñoz-Tuñón


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