The baryon mass function for galaxy clusters
  Context: The evolution of the cluster abundance with redshift is known to be a powerful cosmological constraint when applied to X-ray clusters. Recently, the evolution of the baryon mass function has been proposed as a new variant that is free of the uncertainties present in the temperature-mass relation. A flat model with Omega_matter ~ 0.3 was shown to be preferred in the case of a standard cold dark matter scenario.   Aims: We compared the high redshift predictions of the baryon mass in clusters with data for a more general class of spectra with a varying shape factor Gamma without any restriction to the standard cold dark matter scenario in models normalized to reproduce the local baryon mass function.   Methods: Using various halo mass functions existing in the literature we evaluated the corresponding baryon mass functions for the case of the non-standard power spectra mentioned previously.   Results: We found that models with Omega_matter ~ 1 and Gamma ~ 0.12 reproduce high redshift cluster data just as well as the concordance model does.   Conclusions: Finally, we conclude that the baryon mass function evolution alone does not efficiently discriminate between the more general family of flat cosmological models with non-standard power spectra. 
S. E. Nuza (IAFE), A. Blanchard (LATT)