The Baryonic Halos of Elliptical Galaxies: Radial Distribution of
  Globular Clusters and Diffuse Hot Gas
  For a sample of 9 well-studied giant ellipticals we compare the projected
radial distribution of their red and blue globular cluster (GC) subpopulations
with their host galaxy stellar and X-ray surface brightness profiles. We
support previous findings that the surface density distribution of red
(metal-rich) GCs follows that of the host galaxy starlight. We find good
agreement between the outer slope of the blue GC surface density and that of
the galaxy X-ray emission. This coincidence of projected radial profiles is
likely due to the fact that both blue GCs and X-ray emitting hot gas share the
same gravitational potential in equilibrium. When deprojected the X-ray
emitting hot gas has a radial density dependence that is the square root of
that for the GC density. We further show that the energy per unit mass for blue
GCs is roughly half that of the hot gas.
