Relating basic properties of bright early-type dwarf galaxies to their location in Abell 901/902

Abstract

We present a study of the population of bright early-type dwarf galaxies in the multiple-cluster system Abell 901/902. We use data from the STAGES survey and COMBO-17 to investigate the relation between the color and structural properties of the dwarfs and their location in the cluster. The definition of the dwarf sample is based on the central surface brightness and includes galaxies in the luminosity range −16 ≥ M B > ∼ −19 mag. Using a fit to the color magnitude relation of the dwarfs, our sample is divided into a red and blue subsample. We find a color-density relation in the projected radial distribution of the dwarf sample: at the same luminosity dwarfs with redder colors are located closer to the cluster centers than their bluer counterparts. Furthermore, the redder dwarfs are on average more compact and rounder than the bluer dwarfs. These findings are consistent with theoretical expectations assuming that bright early-type dwarfs are the remnants of transformed late-type disk galaxies involving processes such as ram pressure stripping and galaxy harassment. This indicates that a considerable fraction of dwarf elliptical galaxies in clusters are the results of transformation processes related to interactions with their host cluster.

The evolution of dwarf galaxies in the Coma supercluster

“…Dressler & Gunn 1982;Poggianti et al 2004, but see Goto 2005Yan et al 2009 for an alternative view). In the Coma and Abell 2199 superclusters (z = 0.023), dwarf galaxies show a stronger relation between the SFR and local galaxy density than is found in the more massive galaxies (Haines et al 2006;Mahajan et al 2010a), while elsewhere (Barazza et al 2009) a strong colour-density relation is found in the Abell 901/902 system (z = 0.165). Clusters and rich groups at intermediate and high redshifts (z ∼ 0.5) have more luminous (M V ≤ −20) k+A galaxies, which seem to be missing in rich clusters at z ∼ 0 (Zabludoff et al 1996;Poggianti et al 2004;Nolan, Raychaudhury & Kabán 2007).…”

Galaxy populations in the Antlia cluster - III. Properties of faint early-type galaxies★

“…The luminosity-effective radius diagram presented by Barazza et al (2009) in Abell 901/902 (their fig. 2a) shows that their galaxies scatter about a mean constant effective radius.…”

On the occurrence of galaxy harassment

“…However, the origin of this large population of dEs is still a topic of ongoing debate, partly because they were found to follow a number of continuous relations in structure and colour with bright elliptical and/or lenticular galaxies (e.g. Côté et al 2007;Chen et al 2010;Kormendy & Bender 2012), but also since their identification Appendices are available in electronic form at http://www.aanda.org and detailed analysis are not yet possible at higher shifts (see Barazza et al 2009 for dEs in a z = 0.165 cluster). Clues to the origin of dEs may be given by the presence of weak disk features in a significant fraction of them (Jerjen et al 2000;De Rijcke et al 2003;Lisker et al 2006b), the presence of residual star formation activity in dEs outside of the densest environments (Lisker et al 2006a;Tully & Trentham 2008;Pak et al 2014) and the finding that these have significantly flatter shapes than dEs with low relative velocities in the Virgo cluster core ).…”