Cosmological implications of the full shape of anisotropic clustering measurements in BOSS and eBOSS

TL;DR

This paper analyzes the full shape of anisotropic clustering from BOSS and eBOSS data to constrain cosmological parameters, comparing results with Planck CMB data and exploring the impact of priors on matter power spectrum shape.

Contribution

It provides updated constraints on cosmological parameters using anisotropic clustering measurements with an improved non-linear power spectrum model, and assesses their consistency with Planck data.

Findings

Measured 2=0.805b1 0.049 and =0.815b1 0.044 for  and  scales.

Found a 0.64b1 0.03b5b1 agreement with Planck CMB data.

Low-redshift data suggests a higher E than Planck by 1.7b7b01b7b0b7sigma.

Abstract

We present the analysis of the full shape of anisotropic clustering measurement from the extended Baryon Oscillation Spectroscopic Survey (eBOSS) quasar sample together with the combined galaxy sample from the Baryon Oscillation Spectroscopic Survey (BOSS), re-analysed using an updated recipe for the non-linear matter power spectrum and the non-local bias parameters. We obtain constraints for flat $\Lambda$CDM cosmologies, focusing on the cosmological parameters that are independent of the Hubble parameter $h$. Our recovered value for the RMS linear perturbation theory variance as measured on the scale of $12\,{\rm Mpc}$ is $\sigma_{12}=0.805\pm 0.049$, while using the traditional reference scale of $8\,h^{-1}{\rm Mpc}$ gives $\sigma_{8}=0.815\pm 0.044$. We quantify the agreement between our measurements and the latest CMB data from Planck using the suspiciousness metric, and find them to be consistent within $0.64 \pm 0.03\sigma$. Combining our clustering constraints with the $3\times2$pt data sample from the Dark Energy Survey (DES) Year 1 release slightly degrades this agreement to the level of $1.54 \pm 0.08\sigma$, while still showing an overall consistency with Planck. We furthermore study the effect of imposing a Planck - like prior on the parameters that define the shape of the linear matter power spectrum, and find significantly tighter constraints on the parameters that control the evolution of density fluctuations. In particular, the combination of low-redshift data sets prefers a value of the physical dark energy density $\omega_{\rm DE}=0.335 \pm 0.011$, which is 1.7$\sigma$ higher than the one preferred by Planck.