A comparison is carried out among the star formation histories of the early-type galaxies (ETGs) in fossil groups, clusters and low density environments. Although they show similar evolutionary histories, a significant fraction of the fossils are younger than their counterparts, suggesting that they can be precursors of the isolated ETG galaxies.
Proceedings of 'Stellar populations: planning for the next decade', International Astronomical Union Symposium S262, Rio de Janeiro, Brazil, 03-07 August 2009 / Gustavo R. Bruzual and S. Charlot (eds.),
Vol. 5, pp. 321-322