EAS Publications Series

Issue		EAS Publications Series Volume 20, 2006 Mass Profiles and Shapes of Cosmological Structures
Page(s)		127 - 130
DOI		10.1051/eas:2006058
Published online		19 May 2006

Mass Profiles and Shapes of Cosmological Structures
G.A. Mamon, F. Combes, C. Deffayet and B. Fort (eds)
EAS Publications Series, 20 (2006) 127-130
DOI: 10.1051/eas:2006058

Dark Matter in the Central Regions of Early Type Galaxies

M. Cappellari¹, R. Bacon², M. Bureau³, M.C. Damen¹, R.L. Davies³, P.T. de Zeeuw¹, E. Emsellem², J. Falcón-Barroso¹, D. Krajnovic³, H. Kuntschner⁴, R.M. McDermid¹, R.F. Peletier⁵, M. Sarzi³, R.C.E. van den Bosch¹ and G. van de Ven¹

¹ Leiden Observatory, Postbus 9513, 2300 RA Leiden, The Netherlands
² Centre de Recherche Astrophysique de Lyon, Saint Genis Laval, France
³ Denys Wilkinson Building, University of Oxford, Keble Road, Oxford, UK
⁴ Space Telescope European Coordinating Facility, European Southern Observatory, Germany
⁵ Kapteyn Astronomical Institute, Postbus 800, 9700 AV Groningen, The Netherlands

Abstract
We investigate the well-known correlations between the dynamical mass-to-light ratio M/L and other global observables of elliptical (E) and lenticular (S0) galaxies. We construct two-integral Jeans and three-integral Schwarzschild dynamical models for a sample of 25 E/S0 galaxies with SAURON integral-field stellar kinematics to about one effective (half-light) radius $R_{\rm e}$ . The comparison of the dynamical M/L with the $(M/L)_{\rm pop}$ inferred from the analysis of the stellar population, indicates that dark matter in early-type galaxies contributes ~ $30\%$ of the total mass inside one $R_{\rm e}$ , in agreement with previous studies, with significant variations from galaxy to galaxy. Our results suggest a variation in M/L at constant $(M/L)_{\rm pop}$ , which seems to be linked to the galaxy dynamics. We speculate that fast rotating galaxies have lower dark matter fractions than the slow rotating and generally more massive ones.

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