The build-up of the colour-magnitude relation in galaxy clusters since z∼ 0.8

De Lucia, Gabriella ; Poggianti, Bianca M. ; Aragón-Salamanca, Alfonso ; White, Simon D. M. ; Zaritsky, Dennis ; Clowe, Douglas ; Halliday, Claire ; Jablonka, Pascale ; Von Der Linden, Anja ; Milvang-Jensen, Bo ; Pelló, Roser ; Rudnick, Gregory ; Saglia, Roberto P. ; Simard, Luc

In: Monthly Notices of the Royal Astronomical Society, 2007, vol. 374, no. 3, p. 809-822

Ajouter à la liste personnelle
    Using galaxy clusters from the ESO Distant Cluster Survey, we study how the distribution of galaxies along the colour-magnitude relation has evolved since z∼ 0.8. While red-sequence galaxies in all these clusters are well described by an old, passively evolving population, we confirm our previous finding of a significant evolution in their luminosity distribution as a function of redshift. When compared to galaxy clusters in the local Universe, the high-redshift EDisCS clusters exhibit a significant deficit of faint red galaxies. Combining clusters in three different redshift bins, and defining as ‘faint' all galaxies in the range 0.4 ≳L/L*≳ 0.1, we find a clear decrease in the luminous-to-faint ratio of red galaxies from z∼ 0.8 to ∼0.4. The amount of such a decrease appears to be in qualitative agreement with predictions of a model where the blue bright galaxies that populate the colour-magnitude diagram of high-redshift clusters, have their star formation suppressed by the hostile cluster environment. Although model results need to be interpreted with caution, our findings clearly indicate that the red-sequence population of high-redshift clusters does not contain all progenitors of nearby red-sequence cluster galaxies. A significant fraction of these must have moved on to the red sequence below z∼ 0.8