Cosmological parameter estimation and Bayesian model comparison using VSA data
Abstract
We constrain the basic comological parameters using the first observations by the Very Small Array (VSA) in its extended configuration, together with existing cosmic microwave background data and other cosmological observations. We estimate cosmological parameters for four different models of increasing complexity. In each case, careful consideration is given to implied priors and the Bayesian evidence is calculated in order to perform model selection. We find that the data are most convincingly explained by a simple flat Lambda-CDM cosmology without tensor modes. In this case, combining just the VSA and COBE data sets yields the 68 per cent confidence intervals Omega_b h^2=0.034 (+0.007, -0.007), Omega_dm h^2 = 0.18 (+0.06, -0.04), h=0.72 (+0.15,-0.13), n_s=1.07 (+0.06,-0.06) and sigma_8=1.17 (+0.25, -0.20). The most general model considered includes spatial curvature, tensor modes, massive neutrinos and a parameterised equation of state for the dark energy. In this case, by combining all recent cosmological data, we find, in particular, 95 percent limit on the tensor-to-scalar ratio R < 0.63 and on the fraction of massive neutrinos f_nu < 0.11; we also obtain the 68 per cent confidence interval w=-1.06 (+0.20, -0.25) on the equation of state of dark energy.
Cite
@article{arxiv.astro-ph/0212497,
title = {Cosmological parameter estimation and Bayesian model comparison using VSA data},
author = {Anze Slosar and Pedro Carreira and Kieran Cleary and Rod D. Davies and Richard J. Davis and Clive Dickinson and Ricardo Genova-Santos and Keith Grainge and Carlos M. Gutierrez and Yaser A. Hafez and Michael P. Hobson and Michael E. Jones and Rudiger Kneissl and Katy Lancaster and Anthony Lasenby and J. P. Leahy and Klaus Maisinger and Phil J. Marshall and Guy G. Pooley and Rafael Rebolo and Jose Alberto Rubino-Martin and Ben Rusholme and Richard D. E. Saunders and Richard Savage and Paul F. Scott and Pedro J. Sosa Molina and Angela C. Taylor and David Titterington and Elizabeth Waldram and Robert A. Watson and Althea Wilkinson},
journal= {arXiv preprint arXiv:astro-ph/0212497},
year = {2009}
}
Comments
6 pages, 6 figures, version with minor corrections accepted by MNRAS