This article has an erratum: [erratum]
Volume 548, December 2012
|Number of page(s)||13|
|Published online||26 November 2012|
Formation and evolution of dwarf early-type galaxies in the Virgo cluster
II. Kinematic scaling relations
Departamento de Astrofísica y CC. de la AtmósferaUniversidad Complutense de
e-mail: firstname.lastname@example.org; email@example.com
2 UCO/Lick Observatory, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
3 Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101, USA
4 Laboratoire d’Astrophysique de Marseille-LAM, Université d’Aix-Marseille & CNRS, UMR 7326, 38 rue F. Joliot-Curie, 13388 Marseille Cedex 13, France
5 Kapteyn Astronomical Institute, Postbus 800, 9700 AV Groningen, The Netherlands
6 Instituto de Astrofísica de Canarias, vía Láctea s/n, La Laguna, Tenerife, Spain
7 Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain
8 Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
Received: 2 February 2012
Accepted: 22 October 2012
We place our sample of 18 Virgo dwarf early-type galaxies (dEs) on the (V − K)e-velocity dispersion, Faber-Jackson, and fundamental plane (FP) scaling relations for massive early-type galaxies (Es). We use a generalized velocity dispersion, which includes rotation, to be able to compare the location of both rotationally and pressure supported dEs with those of early and late-type galaxies. We find that dEs seem to bend the Faber-Jackson relation of Es to lower velocity dispersions, being the link between Es and dwarf spheroidal galaxies (dSphs). Regarding the FP relation, we find that dEs are significantly offset with respect to massive hot stellar systems, and re-casting the FP into the so-called κ-space suggests that this offset is related to dEs having a total mass-to-light ratio higher than Es but still significantly lower than dSph galaxies. Given a stellar mass-to-light ratio based on the measured line indices of dEs, the FP offset allows us to infer that the dark matter fraction within the half light radii of dEs is on average ≳42% (uncertainties of 17% in the K band and 20% in the V band), fully consistent with an independent estimate in an earlier paper in this series. We also find that dEs in the size-luminosity relation in the near-infrared, like in the optical, are offset from early-type galaxies, but seem to be consistent with late-type galaxies. We thus conclude that the scaling relations show that dEs are different from Es, and that they further strengthen our previous findings that dEs are closer to and likely formed from late-type galaxies.
Key words: galaxies: clusters: individual: Virgo / galaxies: dwarf / galaxies: evolution / galaxies: elliptical and lenticular, cD / galaxies: formation / galaxies: kinematics and dynamics
© ESO, 2012
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