Dark Radiation and Inflationary Freedom after Planck 2015

Abstract

The simplest inflationary models predict a primordial power spectrum (PPS) of the curvature fluctuations that can be described by a power-law function that is nearly scale-invariant. It has been shown, however, that the low-multipole spectrum of the CMB anisotropies may hint the presence of some features in the shape of the scalar PPS, which could deviate from its canonical power-law form. We study the possible degeneracies of this non-standard PPS with the neutrino anisotropies, the neutrino masses, the effective number of relativistic species and a sterile neutrino or a thermal axion mass. The limits on these additional parameters are less constraining in a model with a non-standard PPS when only including the temperature auto-correlation spectrum measurements in the data analyses. The inclusion of the polarization spectra noticeably helps in reducing the degeneracies, leading to results that typically show no deviation from the $\Lambda$CDM model with a standard power-law PPS.

22 pages, 17 figures, 11 tables. Updated to match the published version. Text abridged upon the referee's requests

References in corpus (17)

• The Clustering of the SDSS DR7 Main Galaxy Sample I: A 4 per cent Distance Measure at z=0.15
• Features and New Physical Scales in Primordial Observables: Theory and Observation
• Light sterile neutrinos
• Relic Neutrinos, thermal axions and cosmology in early 2014
• Cosmological Axion and neutrino mass constraints from Planck 2015 temperature and polarization data
• Beyond six parameters: extending $\Lambda$CDM
• Primordial power spectrum from Planck
• An improved cosmological bound on the thermal axion mass
• Reconstruction of the Primordial Power Spectrum using Temperature and Polarisation Data from Multiple Experiments
• Cosmological constraints on neutrino plus axion hot dark matter
• Search for features in the spectrum of primordial perturbations using Planck and other datasets
• Future cosmological sensitivity for hot dark matter axions
• Reconstruction of the primordial fluctuation spectrum from the five-year WMAP data by the cosmic inversion method with band-power decorrelation analysis
• Pre - Inflationary Clues from String Theory ?
• Light Sterile Neutrinos and Inflationary Freedom
• Primordial Power Spectrum features and $f_{NL}$ constraints
• Robustness of cosmological axion mass limits

Cited by in corpus (24)

• Unveiling $\nu$ secrets with cosmological data: neutrino masses and mass hierarchy
• Recent Advances on Inflation
• Neutrino Mass Ordering from Oscillations and Beyond: 2018 Status and Future Prospects
• Reducing the $H_0$ and ${\sigma }_8$ tensions with Dark Matter-neutrino interactions
• On the improvement of cosmological neutrino mass bounds
• Status of Light Sterile Neutrino Searches
• Co-Decaying Dark Matter
• Dark matter-neutrino interactions through the lens of their cosmological implications
• Calculation of the local density of relic neutrinos
• Cold dark matter plus not-so-clumpy dark relics
• Testing Predictions of the Quantum Landscape Multiverse 2: The Exponential Inflationary Potential
• Cosmology-marginalized approaches in Bayesian model comparison: the neutrino mass as a case study
• Testing for New Physics: Neutrinos and the Primordial Power Spectrum
• Two sides of the same coin: sterile neutrinos and dark radiation. Status and perspectives
• Cosmological bound on neutrino masses in the light of $H_0$ tension
• Red, Straight, no bends: primordial power spectrum reconstruction from CMB and large-scale structure
• Impact of the damping tail on neutrino mass constraints
• Invisible Axion-Like Dark Matter from Electroweak Bosonic Seesaw
• Was there an early reionization component in our universe?
• The impact of theoretical assumptions in the determination of the neutrino effective number from future CMB measurements
• Is it possible to obtain cosmic accelerated expansion through energy transfer between different energy densities?
• Non-thermal Axion Dark Radiation and Constraints
• Exploring Early and Late Cosmology with Next Generation Surveys
• Inflation from a chaotic potential with a step