The Impact of Assuming Flatness in the Determination of Neutrino Properties from Cosmological Data

Abstract

Cosmological data have provided new constraints on the number of neutrino species and the neutrino mass. However these constraints depend on assumptions related to the underlying cosmology. Since a correlation is expected between the number of effective neutrinos N_{eff}, the neutrino mass \sum m_ν, and the curvature of the universe Ω_k, it is useful to investigate the current constraints in the framework of a non-flat universe. In this paper we update the constraints on neutrino parameters by making use of the latest cosmic microwave background (CMB) data from the ACT and SPT experiments and consider the possibility of a universe with non-zero curvature. We first place new constraints on N_{eff} and Ω_k, with N_{eff} = 4.03 +/- 0.45 and 10^3 Ω_k = -4.46 +/- 5.24. Thus, even when Ω_k is allowed to vary, N_{eff} = 3 is still disfavored with 95% confidence. We then investigate the correlation between neutrino mass and curvature that shifts the 95% upper limit of \sum m_ν< 0.45 eV to \sum m_ν< 0.95 eV. Thus, the impact of assuming flatness in neutrino cosmology is significant and an essential consideration with future experiments.

6 pages. 4 figures. Submitted to PRD

References in corpus (13)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Massive neutrinos and cosmology
• Cosmological parameters from combining the Lyman-alpha forest with CMB, galaxy clustering and SN constraints
• Cosmology seeking friendship with sterile neutrinos
• Sterile neutrinos with eV masses in cosmology -- how disfavoured exactly?
• The Case for Dark Radiation
• Limits on Dark Radiation, Early Dark Energy, and Relativistic Degrees of Freedom
• Using BBN in cosmological parameter extraction from CMB: a forecast for Planck
• Neutrinos as cluster dark matter
• Cosmology of neutrinos and extra light particles after WMAP3
• Testing Cosmology with Cosmic Sound Waves
• An improved limit on the neutrino mass with CMB and redshift-dependent halo bias-mass relations from SDSS, DEEP2, and Lyman-Break Galaxies
• Conservative Estimates of the Mass of the Neutrino from Cosmology

Cited by in corpus (12)

• Asymmetric Dark Matter and Dark Radiation
• Constraints on non-flat cosmologies with massive neutrinos after Planck 2015
• Dark Radiation and interacting scenarios
• Cosmology with dropout selection: Straw-man surveys and CMB lensing
• Constraining neutrino mass and extra relativistic degrees of freedom in dynamical dark energy models using Planck 2015 data in combination with low-redshift cosmological probes: basic extensions to $\Lambda$CDM cosmology
• Dark Radiation candidates after Planck
• Spatial curvature endgame: Reaching the limit of curvature determination
• Observational constraints on cosmic neutrinos and dark energy revisited
• Are Light Sterile Neutrinos Preferred or Disfavored by Cosmology?
• Constraints on Neutrino Mass and Light Degrees of Freedom in Extended Cosmological Parameter Spaces
• Dark energy from dark radiation in strongly coupled cosmologies with no fine tuning
• Constraints on Neutrino Mass from Sunyaev--Zeldovich Cluster Surveys