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

¹ Laboratoire d'Astrophysique, École Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, 1290 Versoix, Switzerland e-mail: fabio.barazza@epfl.ch
² Department of Physics, Denys Wilkinson Building, University of Oxford, Keble Road, Oxford, OX1 3RH, UK
³ School of Physics and Astronomy, The University of Nottingham, University Park, Nottingham NG7 2RD, UK
⁴ Department of Astronomy, University of Texas at Austin, 1 University Station, C1400 Austin, TX 78712-0259, USA
⁵ Department of Physics and Astronomy, University Of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
⁶ Department of Physics, 5110 Rockhill Road, University of Missouri-Kansas City, Kansas City, MO 64110, USA
⁷ Institute of Cosmology and Gravitation, Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX, UK
⁸ Institute for Astro- and Particle Physics, University of Innsbruck, Technikerstr. 25/8, 6020 Innsbruck, Austria
⁹ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
¹⁰ Astrophysikalisches Insitut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
¹¹ University of Texas, McDonald Observatory, Fort Davis, TX 79734, USA
¹² SUPA, Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJ, UK
¹³ ESO, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
¹⁴ NRC Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria V9E 2E7, Canada
¹⁵ Centro Hispano Aleman de Calar Alto, C/Jesus Durban Remon 2-2, 04004 Almeria, Spain
¹⁶ Purple Mountain Observatory, National Astronomical Observatories, Chinese Academy of Sciences, Nanjing 210008, PR China

Received: 18 June 2009
Accepted: 16 October 2009

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.