Planck constraints on neutrino isocurvature density perturbations

Abstract

The recent Cosmic Microwave Background data from the Planck satellite experiment, when combined with HST determinations of the Hubble constant, are compatible with a larger, non-standard, number of relativistic degrees of freedom at recombination, parametrized by the neutrino effective number $N_{eff}$. In the curvaton scenario, a larger value for $N_{eff}$ could arise from a non-zero neutrino chemical potential connected to residual neutrino isocurvature density (NID) perturbations after the decay of the curvaton field, parametrized by the amplitude ${\alpha }^{NID}$. Here we present new constraints on $N_{eff}$ and ${\alpha }^{NID}$ from an analysis of recent cosmological data. We found that the Planck+WP dataset does not show any indication for a neutrino isocurvature component, severly constraining its amplitude, and that current indications for a non-standard $N_{eff}$ are further relaxed.

arXiv comment5 pages, 3 figures

References in corpus (21)

• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Efficient Computation of CMB anisotropies in closed FRW models
• Cosmological parameters from CMB and other data: a Monte-Carlo approach
• A 3% Solution: Determination of the Hubble Constant with the Hubble Space Telescope and Wide Field Camera 3
• Generating the curvature perturbation without an inflaton
• A new approach to the evolution of cosmological perturbations on large scales
• The primordial density perturbation in the curvaton scenario
• Relic neutrino decoupling including flavour oscillations
• Adiabatic and entropy perturbations from inflation
• Correlated adiabatic and isocurvature perturbations from double inflation
• Constraining Isocurvature Initial Conditions with WMAP 3-year data
• Cosmological implications of a Relic Neutrino Asymmetry
• Bounds on isocurvature perturbations from CMB and LSS data
• Correlated mixtures of adiabatic and isocurvature cosmological perturbations
• Constraints on isocurvature models from the WMAP first-year data
• Bounds on CDM and neutrino isocurvature perturbations from CMB and LSS data
• The isocurvature fraction after WMAP 3-year data
• WMAP, neutrino degeneracy and non-Gaussianity constraints on isocurvature perturbations in the curvaton model of inflation
• Future constraints on neutrino isocurvature perturbations in the curvaton scenario
• Dark Radiation after Planck
• Constraints on neutrino density and velocity isocurvature modes from WMAP-9 data

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• Lensing Bias to CMB Measurements of Compensated Isocurvature Perturbations
• Probing a panoply of curvaton-decay scenarios using CMB data
• Insights on the Cosmic Origin of Matter from Proton Stability