The Influence of Mass and Environment on the Evolution of Early-Type Galaxies

We report on a uniform comparative analysis of the fundamental parameters of early-type galaxies at z~1 down to MB3×1011 Msolar) with a formation redshift smaller than 2, which cannot be due to selection effects. We report about the changes to the above-mentioned Letter due to an error in the calibration of the galaxy luminosities used by Jørgensen et al. (2006). To correct for this error, the photometry for the two clusters should be offset to brighter luminosities with a factor (1+z). Correcting for this error corresponds to an offset in logL to brighter luminosities with log(1+z), which is 0.26 and 0.28 for RX J0152.7-1357 (z=0.835) and RX J1226.9+3332 (z=0.892), respectively. As a consequence, Figures 1, 2, 3, and 4 are changed as far as the two clusters are concerned, and the correct versions are given here. As can be clearly seen in Figures 1 and 2, the claimed difference in the fundamental plane (FP) and in the M/LB ratio between the clusters and the field environment is not present any more, and the behavior of the z~1 early-type galaxies (ETGs) is remarkably similar in both environments, as claimed earlier by di Serego Alighieri et al. (2005). Therefore, the estimated formation epoch of ETGs does not depend on the environment but only on the galaxy mass (see Fig. 3). Quantitatively, the mean age difference between clusters and the field in each mass bin is smaller than 5% and is well within the standard deviation due to galaxy-to-galaxy variations (Fig. 4). Clearly it is now no longer relevant to study this age difference as a function of galaxy mass, and so Figure 4 is modified accordingly. Our correct results are therefore in even larger contrast to the most recent incarnation of the hierarchical models of galaxy formation and evolution, which foresee a marked difference in the formation epoch of ETGs with environment (De Lucia et al. 2006)