Observational bounds on the cosmic radiation density

Abstract

We consider the inference of the cosmic radiation density, traditionally parameterised as the effective number of neutrino species N_eff, from precision cosmological data. Paying particular attention to systematic effects, notably scale-dependent biasing in the galaxy power spectrum, we find no evidence for a significant deviation of N_eff from the standard value of N_eff^0=3.046 in any combination of cosmological data sets, in contrast to some recent conclusions of other authors. The combination of all available data in the linear regime prefers, in the context of a ``vanilla+N_eff'' cosmological model, 1.1<N_eff<4.8 (95% C.L.) with a best-fit value of 2.6. Adding data at smaller scales, notably the Lyman-alpha forest, we find 2.2<N_eff<5.8 (95% C.L.) with 3.8 as the best fit. Inclusion of the Lyman-alpha data shifts the preferred N_eff upwards because the sigma_8 value derived from the SDSS Lyman-alpha data is inconsistent with that inferred from CMB. In an extended cosmological model that includes a nonzero mass for N_eff neutrino flavours, a running scalar spectral index and a w parameter for the dark energy, we find 0.8<N_eff<6.1 (95% C.L.) with 3.0 as the best fit.

23 pages, 3 figures, uses iopart.cls; v2: 1 new figure, references added, matches published version

References in corpus (38)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• Detection of the Baryon Acoustic Peak in the Large-Scale Correlation Function of SDSS Luminous Red Galaxies
• Cosmological parameters from SDSS and WMAP
• Cosmological parameters from CMB and other data: a Monte-Carlo approach
• Final Results from the Hubble Space Telescope Key Project to Measure the Hubble Constant
• The Supernova Legacy Survey: Measurement of Omega_M, Omega_Lambda and w from the First Year Data Set
• The 2dF Galaxy Redshift Survey: Power-spectrum analysis of the final dataset and cosmological implications
• Stable clustering, the halo model and nonlinear cosmological power spectra
• The 3D power spectrum of galaxies from the SDSS
• New Hubble Space Telescope Discoveries of Type Ia Supernovae at z > 1: Narrowing Constraints on the Early Behavior of Dark Energy
• Cosmological Constraints from the SDSS Luminous Red Galaxies
• Three Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Polarization Analysis
• Three-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Temperature Analysis
• Relic neutrino decoupling including flavour oscillations
• Cosmological parameters from combining the Lyman-alpha forest with CMB, galaxy clustering and SN constraints
• The Nature of Galaxy Bias and Clustering
• The Linear Theory Power Spectrum from the Lyman-alpha Forest in the Sloan Digital Sky Survey
• The shape of the SDSS DR5 galaxy power spectrum
• The Scale Dependence of Halo and Galaxy Bias: Effects in Real Space
• Neutrino masses and the number of neutrino species from WMAP and 2dFGRS
• Cosmological and astrophysical parameters from the SDSS flux power spectrum and hydrodynamical simulations of the Lyman-alpha forest
• Neutrino masses and the dark energy equation of state - relaxing the cosmological neutrino mass bound
• Effective number of neutrinos and baryon asymmetry from BBN and WMAP
• The neutrino mass bound from WMAP-3, the baryon acoustic peak, the SNLS supernovae and the Lyman-alpha forest
• Current cosmological bounds on neutrino masses and relativistic relics
• Current cosmological constraints from a 10 parameter CMB analysis
• Cosmological mass limits on neutrinos, axions, and other light particles
• Redshift space bias and beta from the halo model
• Measuring neutrino masses and dark energy with weak lensing tomography
• The Lyman-alpha forest and WMAP year three
• Time Evolution of Galaxy Formation and Bias in Cosmological Simulations
• Present bounds on the relativistic energy density in the Universe from cosmological observables
• Neutrino masses and cosmic radiation density: Combined analysis
• Measuring the cosmological background of relativistic particles with WMAP
• Constraints on the cosmic neutrino background
• Cosmology of neutrinos and extra light particles after WMAP3
• Constraint on the Effective Number of Neutrino Species from the WMAP and SDSS LRG Power Spectra
• Testing the accuracy of the Hydro-PM approximation in numerical simulations of the Lyman-alpha forest

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