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Title: Accuracy of cosmological parameters using the baryon acoustic scale

Percent-level measurements of the comoving baryon acoustic scale standard ruler can be used to break degeneracies in parameter constraints from the CMB alone. The sound horizon at the epoch of baryon drag is often used as a proxy for the scale of the peak in the matter density correlation function, and can conveniently be calculated quickly for different cosmological models. However, the measurements are not directly constraining this scale, but rather a measurement of the full correlation function, which depends on the detailed evolution through decoupling. We assess the level of reliability of parameter constraints based on a simple approximation of the acoustic scale compared to a more direct determination from the full numerical two-point correlation function. Using a five-parameter fitting technique similar to recent BAO data analyses, we find that for standard ΛCDM models and extensions with massive neutrinos and additional relativistic degrees of freedom, the approximation is at better than 0.15% for most parameter combinations varying over reasonable ranges.
Authors:
;  [1]
  1. Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom)
Publication Date:
OSTI Identifier:
22382015
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 01; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCURACY; APPROXIMATIONS; BARIUM OXIDES; BARYONS; COMPARATIVE EVALUATIONS; CORRELATION FUNCTIONS; DATA ANALYSIS; DEGREES OF FREEDOM; DENSITY; LIMITING VALUES; NEUTRINOS; PEAKS; RELATIVISTIC RANGE