Concentrations of Dark Halos from Their Assembly Histories

  title={Concentrations of Dark Halos from Their Assembly Histories},
  author={Risa H. Wechsler and James S Bullock and Joel R. Primack and Andrey V. Kravtsov and Avishai Dekel},
  journal={The Astrophysical Journal},
  pages={52 - 70}
We study the relation between the density profiles of dark matter halos and their mass assembly histories using a statistical sample of halos in a high-resolution N-body simulation of the ΛCDM cosmology. For each halo at z = 0, we identify its merger history tree and determine concentration parameters cvir for all progenitors, thus providing a structural merger tree for each halo. We fit the mass accretion histories by a universal function with one parameter, the formation epoch ac, defined… 
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