X-ray Observations of Optically Selected Giant Elliptical-Dominated   Galaxy Groups
  We present a combined optical and X-ray analysis of three optically selected X-ray bright groups with giant elliptical galaxies in the center. These massive ellipticals were targeted for XMM-Newton X-ray observations based on their large velocity dispersions and their proximity to a nearby ROSAT X-ray source. Additionally, these targets are significantly brighter in the optical than their nearest neighbors. We show that one of these systems meets the standard criteria for a fossil group. While the other two systems have a prominent magnitude gap in the E/S0 ridgeline, they do not appear to have reached the fossil-like final stage of group evolution. 
Alexey Voevodkin, Christopher J. Miller, Konstantin Borozdin, Katrin   Heitmann, Salman Habib, Paul Ricker, Robert C. Nichol