Key points are not available for this paper at this time.
The tightness of the observed colour-magnitude and Mg₂- velocity dispersion relations for elliptical galaxies has often been cited as an argument against a picture in which ellipticals form by the merging of spiral disks. A common view is that merging would mix together stars of disparate ages and produce a large scatter in these relations. Here I use semi-analytic models of galaxy formation to derive the distribution of the mean ages, colours and metallicities of the stars in elliptical galaxies formed by mergers in a flat CDM universe. It is seen that most of the stars in ellipticals form at relatively high redshift (z > 1. 9) and that the predicted scatter in the colour-magnitude and Mg₂ - sigma relations falls within observational bounds. I conclude that the apparent homogeneity in the properties of the stellar populations of ellipticals is not inconsistent with a merger scenario for the origin of these systems.
G. Kauffmann (Thu,) studied this question.