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Keywords:

  • galaxies: formation;
  • cosmology: theory;
  • large-scale structure of Universe

ABSTRACT

The present paper extends a previous study of Del Popolo to clusters of galaxies, considering how baryon–dark matter (DM) interplay shapes the density profiles of dwarf galaxies. Cluster density profiles are determined taking into account dynamical friction, random and ordered angular momentum and the response of DM haloes to condensation of baryons. We find that haloes containing only DM are characterized by Einasto’s profiles, and that profiles flatten with increasing content of baryons and increasing values of random angular momentum. The analytical results obtained in the first part of the paper are applied to well-studied clusters, the inner profiles of which have slopes flatter than Navarro, Frenk & White (NFW) predictions (A611, A383) or are characterized by profiles in agreement with the NFW model (MACS J1423.8+2404, RXJ1133). By using an independently measured baryonic fraction and a typical spin parameter value λ≃ 0.03 and adjusting the random angular momentum, we re-obtain the mass and density profiles of the quoted clusters. Finally, we show that the baryonic mass inside ≃10 kpc, Mb, in, is correlated with the total mass of the clusters as inline image.