Dark Matter in Elliptical Galaxies

While the brightest group and cluster dominant elliptical galaxies are believedto have large dark matter halos, recent dynamical measurements suggest that somemoderate luminosity ellipticals contain little or no dark matter. However, anXray mass measurement for one of these galaxies produces a conflicting result.We have undertaken the first systematic survey of mass profiles in ordinaryellipticals with Xray halos using archival data, but almost all the galaxieswith Xray data available lie in high density environments. In order to rectifythis bias, we propose to observe four elliptical galaxies in low densityenvironments with the goal of understanding their halo properties. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]