Tension between the power spectrum of density perturbations measured on large and small scales

Battye, Richard; Charnock, Tom; Moss, Adam

Abstract

There is a tension between measurements of the amplitude of the power spectrum of density perturbations inferred using the cosmic microwave background (CMB) and directly measured by large-scale structure (LSS) on smaller scales. We show that this tension exists, and is robust, for a range of LSS indicators including clusters, lensing and redshift space distortions and using CMB data from either Planck or WMAP+SPT/ACT. One obvious way to try to reconcile this is the inclusion of a massive neutrino which could be either active or sterile. Using Planck and a combination of all the LSS data we find that (i) for an active neutrino ∑mν=(0.357±0.099)  eV and (ii) for a sterile neutrino meffsterile=(0.67±0.18)  eV and ΔNeff=0.32±0.20. This is, however, at the expense of a degraded fit to Planck temperature data, and we quantify the residual tension at 2.5σ and 1.6σ for massive and sterile neutrinos, respectively. We also consider alternative explanations including a lower redshift for reionization that would be in conflict with polarization measurements made by WMAP and ad hoc modifications to the primordial power spectrum.

Citation

Battye, R., Charnock, T., & Moss, A. (2015). Tension between the power spectrum of density perturbations measured on large and small scales. Physical Review D, 91(10), https://doi.org/10.1103/PhysRevD.91.103508

• Journal Article Type: Article
• Acceptance Date: Feb 1, 2015
• Online Publication Date: May 12, 2015
• Publication Date: May 15, 2015
• Deposit Date: Sep 21, 2017
• Publicly Available Date: Oct 9, 2020
• Journal: Physical Review D
• Print ISSN: 2470-0010
• Electronic ISSN: 2470-0029
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 91
• Issue: 10
• Article Number: 103508
• DOI: https://doi.org/10.1103/PhysRevD.91.103508
• Public URL: https://nottingham-repository.worktribe.com/output/1114175
• Publisher URL: https://journals.aps.org/prd/abstract/10.1103/PhysRevD.91.103508
• PMID: 00035436