A simulated τCDM cosmology cluster catalogue: the NFW profile and the temperature-mass scaling relations

We have extracted over 400 clusters, covering more than two decades in mass, from three simulations of the τCDM cosmology. This represents the largest uniform catalogue of simulated clusters ever produced. The clusters exhibit a wide variety of density profiles. Only a minority are well-fitted in their outer regions by the widely used density profile of Navarro, Frenk & White (NFW), which is applicable to relaxed haloes. Others have steeper outer density profiles, show sharp breaks in their density profiles, or have significant substructure. If we force a fit to the NFW profile, then the best-fitting concentrations decline with increasing mass, but this is driven primarily by an increase in substructure as one moves to higher masses. The temperature—mass relations for properties measured within a sphere enclosing a fixed overdensity all follow the self-similar form, T∝M2/3; however, the normalization is lower than the value inferred for observed clusters. The temperature—mass relations for properties measured within a fixed physical radius are significantly steeper then this. Both can be accurately predicted using the NFW model.