Age distribution of cluster and field ellipticals. Left − the distribution of the age of the stellar population of field elliptical galaxies (blue shaded histogram) is compared with the age distribution of all the cluster ellipticals (red shaded histogram).The colored solid lines mark the median values of the distributions (see text). Right − same as left panel but in this case the comparison is made by considering field and cluster ellipticals in the same mass range, that is, by excluding cluster galaxies with masses larger than log (ℳ_∗) = 11.1 M_⊙.