Chandra Observations and the Mass Distribution of EMSS1358+6245: Toward Constraints on Properties of Dark Matter

Chandra observations of lensing galaxy clusters have now provided accurate dark matter profiles for several objects in which the intracluster medium is likely to be in hydrostatic equilibrium. We discuss Chandra observations of the mass profile of one such cluster, EMSS1358+6245. We find no evidence for flattening of the mass density profile at radii greater than 50/h_50 kpc . This result, and similar findings from Chandra observations of other clusters, appear to rule out models in of dark matter self-interaction proposed to explain the flat cores of low-surface brightness galaxies.