Constraining the Age of Fossil Groups with Chandra
Renato Dupke (University of Michigan) , Claudia Mendes de Oliveira (University of Sao Paulo, Brazil)
Indications that fossil groups are formed at early epochs come not just from the expected high time scale for dynamical friction to merge the core galaxies, but also from recent X-ray observations, including high concentration parameters and featureless X-ray morphologies. However, the lack of cooling cores in fossil groups with short cooling times and the sensitiveness of the dynamical friction time scale on the satellite galaxies’ impact parameter are also consistent with a more recent formation time. Here, we discuss new constraints on the formation time of fossil groups based on the residual chemical profiles of the intra-group gas as measured by X-ray elemental abundance ratios.