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Title: Halo model and halo properties in Galileon gravity cosmologies

We investigate the performance of semi-analytical modelling of large-scale structure in Galileon gravity cosmologies using results from N-body simulations. We focus on the Cubic and Quartic Galileon models that provide a reasonable fit to CMB, SNIa and BAO data. We demonstrate that the Sheth-Tormen mass function and linear halo bias can be calibrated to provide a very good fit to our simulation results. We also find that the halo concentration-mass relation is well fitted by a power law. The nonlinear matter power spectrum computed in the halo model approach is found to be inaccurate in the mildly nonlinear regime, but captures reasonably well the effects of the Vainshtein screening mechanism on small scales. In the Cubic model, the screening mechanism hides essentially all of the effects of the fifth force inside haloes. In the case of the Quartic model, the screening mechanism leaves behind residual modifications to gravity, which make the effective gravitational strength time-varying and smaller than the standard value. Compared to normal gravity, this causes a deficiency of massive haloes and leads to a weaker matter clustering on small scales. For both models, we show that there are realistic halo occupation distributions of Luminous Red Galaxies that canmore » match both the observed large-scale clustering amplitude and the number density of these galaxies.« less
Authors:
; ; ;  [1] ;  [2] ;  [3]
  1. Institute for Computational Cosmology, Department of Physics, Durham University, South Road, Durham, DH1 3LE (United Kingdom)
  2. Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom)
  3. Institute for Particle Physics Phenomenology, Department of Physics, Durham University, South Road, Durham, DH1 3LE (United Kingdom)
Publication Date:
OSTI Identifier:
22373630
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2014; Journal Issue: 04; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMOLOGY; DENSITY; DISTRIBUTION; GALAXIES; GRAVITATION; MASS; MODIFICATIONS; NONLINEAR PROBLEMS; PERFORMANCE