2012/01/31 by Michele Moresco, Licia Verde, Lucia Pozzetti +2 · 7 citations
Physics and Astronomy · #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Particle physics theoretical and experimental studies #astro-ph.CO #hep-ph
paper · pdf · doi:10.1088/1475-7516/2012/07/053
published as JCAP07(2012)053 · 18 pages, 17 figures, 7 tables, published in JCAP. It is a companion to Moresco et al. (2012a, http://arxiv.org/abs/1201.3609) and Jimenez et al. (2012, http://arxiv.org/abs/1201.3608). The H(z) data can be downloaded at http://www.physics-astronomy.unibo.it/en/research/areas/astrophysics/cosmology-with-cosmic-chronometers
openalex publication_date 2012/07/31 · arxiv created 2013/02/05 · arxiv updated 2013/02/06 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/04
We have assembled a compilation of observational Hubble parameter measurements estimated with the differential evolution of cosmic chronometers, in the redshift range 0 < z < 1.75. This sample has been used, in combination with CMB data and with the most recent estimate of the Hubble constant H 0 , to derive new constraints on several cosmological parameters. The new Hubble parameter data are very useful to break some of the parameter degeneracies present in CMB-only analysis, and to constrain possible deviations from the standard (minimal) flat ΛCDM model. The H ( z ) data are especially valuable in constraining Ω k and Ω DE in models that allow a variation of those parameters, yielding constraints that are competitive with those obtained using Supernovae and/or baryon acoustic oscillations. We also find that our H ( z ) data are important to constrain parameters that do no affect directly the expansion history, by breaking or reducing degeneracies with other parameters. We find that N rel = 3.45±0.33 using WMAP 7-years data in combination with South Pole Telescope data and our H ( z ) determinations ( N rel = 3.71±0.45 using Atacama Cosmology Telescope data instead of South Pole Telescope). We exclude N rel > 4 at 95% CL (74% CL) using the same datasets combinations. We also put competitive limits on the sum of neutrino masses, Σ m ν < 0.24 eV at 68% confidence level. These results have been proven to be extremely robust to many possible systematic effects, such as the initial choice of stellar population synthesis model adopted to estimate H ( z ) and the progenitor-bias.