The measurements of matter density perturbations amplitude from cosmological data

TL;DR

This paper compares various measurements of the matter density perturbation amplitude, highlighting a significant discrepancy in the Planck CMB lensing data at high multipoles, which affects combined cosmological analyses.

Contribution

It identifies and quantifies inconsistencies in $\sigma_8$ measurements from different cosmological data sets, emphasizing the need to exclude certain Planck data from combined analyses.

Findings

Planck CMB lensing data at high multipoles contradicts other measurements at 3.7σ

Most measurements agree on $\sigma_8=0.792\, ext{±}\,0.006$

Excluding high multipole lensing data yields consistent cosmological parameters

Abstract

We compare various physically different measurements of linear matter density perturbation amplitude, $sigma_8$, which are obtained from the observations of CMB anisotropy, galaxy cluster mass function, weak gravitation lensing, matter power spectrum and redshift space distortions. We show that $\sigma_8$ measurement from CMB gravitational lensing signal based on Planck CMB temperature anisotropy data at high multipoles, $\ell>1000$, contradict to all other measurements obtained both from remaining Planck CMB anisotropy data and from other cosmological data, at about $3.7\sigma$ significance level. Therefore, these data currently should not be combined with other data to constrain cosmological parameters. With the exception of Planck CMB temperature anisotropy data at high multipoles, all other measurements are in good agreement between each other and give the following measurements of linear density perturbation amplitude: $\sigma_8=0.792\pm0.006$, mean density of the Universe: $\Omega_m=0.287\pm0.007$, and Hubble constant: $H_0 = 69.4\pm 0.6$~km~s$^{-1}$~Mpc$^{-1}$. Taking in account the data on baryon acoustic oscillations and (or) direct measurements of the Hubble constant, one can obtain different constraints on sum of neutrino mass and number of relativistic species.