| 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. |