Over-Luminous Elliptical Galaxies

We propose to observe three normal, bright, (relatively) isolated ellipticalgalaxies that are surrounded by extended dark matter and hot gas halos typicalof poor clusters, with spatial extents of 5001000 kpc. These systems, selectedfrom Xray surveys, are probably fossil groups, systems whose bright galaxieshave merged into a single bright galaxy. With XMMNewton, we will deriveaccurate gas density and temperature profiles to test mass distributionpredictions from numerical simulations, investigate any cooling gas in thecenters, determine the star formation history, inventory the stellar componentthrough the abundance determinations, and test formation theories of fossilgroups to determine their relationship to more typical groups and clusters. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]