Mon. Not. R. Astron. Soc., 437, 3670-3687 (2014/February-1)
Modelling mass distribution in elliptical galaxies: mass profiles and their correlation with velocity dispersion profiles.
CHAE K.-H., BERNARDI M. and KRAVTSOV A.V.
Abstract (from CDS):
We assemble a statistical set of global mass models for ∼ 2000 nearly spherical Sloan Digital Sky Survey (SDSS) galaxies at a mean redshift of <z> = 0.12 based on their aperture velocity dispersions and newly derived luminosity profiles in conjunction with published velocity dispersion profiles and empirical properties and relations of galaxy and halo parameters. When two-component (i.e. stellar plus dark) mass models are fitted to the SDSS aperture velocity dispersions, the predicted velocity dispersion profile (VP) slopes within the effective (i.e. projected half-light) radius Reff match well the distribution in observed elliptical galaxies. From a number of input variations the models exhibit for the radial range 0.1Reff < r < Reff a tight correlation <γe> = (1.865±0.008) + (-4.93±0.15)<η> where <γe> is the mean slope absolute value of the total mass density and <η> is the mean slope of the velocity dispersion profile, which leads to a super-isothermal <γe> = 2.15±0.04 for <η> = -0.058±0.008 in observed elliptical galaxies. Furthermore, the successful two-component models appear to imply a typical slope curvature pattern in the total mass profile because for the observed steep luminosity (stellar mass) profile and the weak lensing inferred halo profile at large radii a total mass profile with monotonically varying slope would require too high dark matter density in the optical region giving rise to too large aperture velocity dispersion and too shallow VP.