NOAO >   Observing Info >   Approved Programs >   2005A-0172

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Proposal Information for 2005A-0172


PI: Ewan O'Sullivan, SAO, ejos@head.cfa.harvard.edu
Address: SAO, 60 GARDEN STREET MS-67, CAMBRIDGE, MA 02138, USA

CoI: Habib Khosroshahi, University of Birmingham
CoI: Laurence Jones, University of Birmingham
CoI: Trevor Ponman, University of Birmingham
CoI: Somak Raychaudhury, University of Birmingham

Title: Multi-wavelength study of local fossil groups

Abstract: The cores of galaxy groups with low velocity dispersions are probably the most suitable site for galaxy mergers. Fossil groups, with a dominant giant elliptical galaxy and no other L* galaxies, are likely to be the end results of multiple mergers, with dwarf galaxies and an X- ray halo left behind. Fossil groups are as numerous as galaxy clusters, so they may be the site where some giant ellipticals in clusters - as well as isolated field ellipticals - were formed, depending on the relative isolation of the fossil group. Using the imaging data from the KP-0.9m/MOSA we will identify the group members using galaxy colors, and study the morphology of the member galaxies. Later spectroscopic observation will be based on this color selection. We will quantify the luminosity distribution, and hence the mass to light ratio, using existing and/or proposed XMM and Chandra X-ray observations. We will make a comparison between the optical galaxy luminosity function of fossil and non-fossil groups to find out how fossil groups fit in to the two distinct classes of X-ray bright and dim groups in terms of their galaxy luminosity function as well as the morphology of their constituent galaxies.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2005A-0172

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