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D.J. Horner (University of Maryland/Goddard Space Flight Center), R.F. Mushotzky (NASA/GSFC), C.S. Scharf (STScI)
We examine the relationship between the mass and x-ray gas temperature of galaxy clusters using data drawn from the literature. Simple theoretical arguments suggest that the mass of a cluster is related to the x-ray temperature as M \propto T\rm x3/2. Virial theorem mass estimates based on cluster galaxy velocity dispersions seem to be accurately described by this scaling with a normalization consistent with that predicted by the simulations of Evrard, Metzler, & Navarro (1996). X-ray mass estimates which employ spatially resolved temperature profiles also follow T\rm x3/2 scaling although with a normalization about 40% lower than that of the fit to the virial masses. However, the isothermal \beta-model and x-ray surface brightness deprojection show steeper power law indices (~1.8-2.0). The steepness of the isothermal estimates is due to their implied dark matter density profile of \rho(r) \propto r-2 at large radii while observations and simulations suggest that clusters follow steeper profiles (e.g.\ \rho(r) \propto r-2.4). The gas distribution is also seen to be a function of T\rm x, consistent with a history of non-gravitational energy input.