EAS Publications Series

Mass Profiles and Shapes of Cosmological Structures
G.A. Mamon, F. Combes, C. Deffayet and B. Fort (eds)
EAS Publications Series, 20 (2006) 131-134
DOI: 10.1051/eas:2006059

Mass-to-light ratios of ellipticals in $\Lambda$ CDM

N.R. Napolitano¹ and PN.S team²

¹ INAF-Observatory of Capodimonte, Naples, Italy
² Planetary Nebula Spectrograph team: see http:/ $\!$ /www.astro.rug.nl/~pns/pns_team.html#coll

Abstract
We use the mass-to-light gradients in early-type galaxies to infer the global dark matter fraction, $f_{\rm d}=M_{\rm d}/M_{\rm *}$ , for these systems. We discuss implications about the total star formation efficiency in dark-matter halos and show that the the trend of $f_{\rm d}$ with mass produces virial mass-to-light ratios which are consistent semi-analitical models. Preliminary kurtosis analysis of the quasi-constant M/L galaxies in Romanowsky et al. seems at odd with Dekel et al. simulations.

Mass-to-light ratios of ellipticals in CDM

Mass-to-light ratios of ellipticals in $\Lambda$ CDM