Formation and evolution of stellar population based on the red passive galaxies observed up to z ∼ 12017.02.06 11:53 - admin
We would like to present the studies over the evolution and the star formation history of passive galaxies observed by the VIMOS Public Extragalactic Redshift Survey (VIPERS). We compare the 4000 Å break (D4000n) and the Hδ Lick index (HδA) measured on VIPERS stacked spectra with a grid of synthetic spectra to constrain the star formation epochs of these galaxies. Assuming a single burst formation, we find that high-mass passive galaxies formed their stars at zform~2, while low-mass galaxies formed their main stellar population more recently, at zform~1. The consistency of these results, obtained using two independent estimator of the formation redshift (D4000 and HδA), further strengthens a scenario in which star formation proceeds from higher- to lower-mass systems as time passes, i. e. what has become known as the 'downsizing' picture.