Por Pier-Stefano Corasaniti (Observatoire de Paris-Meudon, France).
Survey of galaxy clusters can provide cosmological parameter constraints through measurements of the cluster abundance. This requires the ability to accurately predict the halo mass function (HMF) for a given set of cosmological parameters. The standard approach consists in assuming a parametrized function calibrated against N-body simulations. However, an approximately universal form of the HMF is recovered only in the case of halo masses defined at the virial overdensity. Cluster masses on the other hand are never estimated at such large radii. This requires the use of a mapping of the halo mass function to the observed mass definition, thus linking the halo abundance to the halo mass profile. I will discuss the implication of such a mapping for cluster cosmology and the systematic errors that the adoption of different mapping approaches introduce in the cosmological parameter inference analysis.
