In the context of recent observational results that show massive ellipticals were in place at high redshifts , we reassess the status of monolithic collapse in a \Lambda CDM universe .
Using a sample of over 2000 galaxies from the Sloan Digital Sky Survey , by comparing the dynamical mass and stellar mass ( estimated from colours ) we find that ellipticals have ‘ cores ’ which are baryon-dominated within their half-light radius .
These galaxies correspond to 3-sigma peaks in the spherical collapse model if the total mass in the halo is assumed to be 20 times the dynamical mass within the half-light radius .
This value yields stellar mass to total mass ratios of 8 % , compared to a cosmological baryon fraction of 18 % derived from WMAP3 alone .
We further develop a method for reconstructing the concentration halo parameter c of the progenitors of these galaxies by utilizing adiabatic contraction .
Although the analysis is done within the framework of monolithic collapse , the resulting distribution of c is log-normal with a peak value of c \sim 3 - 10 and a distribution width similar to the results of N-body simulations .
We also derive scaling relations between stellar and dynamical mass and the velocity dispersion , and find that these are sufficient to recover the tilt of the fundamental plane .