I. Internal kinematics
Departamento de Astrofísica y CC. de la AtmósferaUniversidad Complutense de
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2 Laboratoire d’Astrophysique de Marseille, UMR 6110 CNRS, 38 rue F. Joliot-Curie, 13388 Marseille, France
3 Centro de Estudios de Física del Cosmos de Aragón, 44001 Teruel, Spain
4 Kapteyn Astronomical Institute, Rijksuniversiteit Groningen, Postbus 800, 9700 AV Groningen, The Netherlands
5 National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475, USA
Accepted: 12 November 2010
We present new medium resolution kinematic data for a sample of 21 dwarf early-type galaxies (dEs) mainly in the Virgo cluster, obtained with the WHT and INT telescopes at the Roque de los Muchachos Observatory (La Palma, Spain). These data are used to study the origin of the dwarf elliptical galaxy population inhabiting clusters. We confirm that dEs are not dark matter dominated galaxies, at least not up to the half-light radius. We also find that the observed galaxies in the outer parts of the cluster are mostly rotationally supported systems with disky morphological shapes. Rotationally supported dEs have rotation curves similar to those of star-forming galaxies of similar luminosity and follow the Tully-Fisher relation. This is expected if dE galaxies are the descendants of low-luminosity star-forming systems that have recently entered the cluster environment and lost their gas due to a ram-pressure stripping event, quenching their star formation activity and transforming into quiescent systems, but conserving their angular momentum.
Key words: galaxies: clusters: individual: Virgo / galaxies: dwarf / galaxies: elliptical and lenticular, cD / galaxies: kinematics and dynamics / galaxies: evolution / galaxies: formation
Appendices, Full Fig. 6, and Fig. 7 are only available in electronic form at http://www.aanda.org.
Full Table 3 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (22.214.171.124) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/526/A114
© ESO, 2011