2004ApJ...601L..33V

We explore possible correlations between light profile shapes, as parameterized by the Sérsic index n or the concentration index C_re((1)/(3)), and relevant stellar population parameters in early-type galaxies. Mean luminosity-weighted ages, metallicities, and abundance ratios were obtained from spectra of very high signal-to-noise ratio and stellar population models that synthesize galaxy spectra at the resolution given by their velocity dispersions, σ, in combination with an age indicator (Hγ_σ) that is virtually free of the effects of metallicity. We do not find any significant correlation between n [or C_re((1)/(3))] and mean age or metallicity, but we do find a strong positive correlation of the shape parameters with Mg/Fe abundance ratio. This dependence is as strong as the Mg/Fe-σ and C_re((1)/(3))-σ relations. We speculate that early-type galaxies settle up their structure on timescales in agreement with those imposed by their Mg/Fe ratios. This suggests that the global structure of larger galaxies, with larger Mg/Fe ratios and shorter timescales, was already in place at high z, without experiencing a significant time evolution.