Stellar Populations of Fossil Group Galaxies

Type Conference Paper
Names Naomi Pequette, K. Alexander, E. M. Wilcots
Proceedings Title Bulletin of the American Astronomical Society
Conference Name American Astronomical Society, AAS Meeting #217, #335.11
Volume 43
Pages 33511
Date January 1, 2011
Library Catalog NASA ADS
Abstract Fossil groups are thought to be the remnants of groups of galaxies in which all the component galaxies have merged. Left behind is one, large, elliptical galaxy (sometimes surrounded by faint remnants of the group), which has a mass and X-ray luminosity comparable to an entire group of galaxies. It is thought that these objects are the end state of evolution for a galaxy group and have not undergone a major merger in the past 1 Gyr. This makes them ideal for studying characteristics intrinsic to the group environment. We studied a sample of seven candidate fossil groups, selected from Santos et al. 2007, using the SparsePak Integral Field Unit and Bench Spectrograph on the WIYN 3.5m telescope (Kitt Peak, AZ). Here, we present the results of our spectroscopic survey. We correlated our data with multi-wavelength observations of these galaxies, including the Hess et al. (2010) radio continuum observations, and found evidence of AGN activity. To better understand if the AGN is correlated with the star formation history of the fossil group, we used our spectroscopic data and data from SDSS to investigate the stellar populations of the central elliptical galaxies. Fitting these data with a stellar population synthesis model, we find that the star formation history of these galaxies is broadly consistent with the theory that these galaxy groups formed through minor mergers. This research was supported by the NSF/REU grant AST-1004881 and the University of Wisconsin-Madison.
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