New cosmological constraints with extended-Baryon Oscillation Spectroscopic Survey DR14 quasar sample

Lu Chen,Qing-Guo Huang,Ke Wang

doi:10.1140/epjc/s10052-017-5344-1

Abstract

We update the constraints on the cosmological parameters by adopting the Planck data released in 2015 and baryon acoustic oscillation (BAO) measurements including the new DR14 quasar sample measurement at redshift z=1.52, and we conclude that the six-parameter Lambda CDM model is preferred. Exploring some extensions to the Lambda CDM model, we find that the equation of state of dark energy reads w=-1.036pm 0.056 in the wCDM model, the effective number of relativistic degrees of freedom in the Universe is N_text {eff}=3.09_{-0.20}^{+0.18} in the N_text {eff}+Lambda CDM model and the spatial curvature parameter is Omega _k=(1.8pm 1.9)times 10^{-3} in the Omega _k+Lambda CDM model at 68% confidence level (C.L.), and the 95% C.L. upper bounds on the sum of three active neutrinos masses are sum m_nu <0.16 eV for the normal hierarchy (NH) and sum m_nu <0.19 eV for the inverted hierarchy (IH) with Delta chi ^2equiv chi ^2_text {NH}-chi ^2_text {IH}=-1.25.

Highlights

The accuracy of cosmological observations has been significantly improved in the past two decades
CDM model is strongly supported by the precise measurements of anisotropies of the cosmic microwave background (CMB) [1,2]
The Type Ia supernova (SNe) [3,4] and baryon acoustic oscillation (BAO) data [5,6] as a geometric complement directly encode the information of the history of the expansion in the late-time Universe

Summary

Introduction

The accuracy of cosmological observations has been significantly improved in the past two decades. The BAO measurement is the periodic relic of fluctuations of baryonic matter density in the Universe It is considered as a standard ruler of the Universe and can be used as an independent way to constrain models. With increasing total active neutrino mass at fixed θ∗, the spherically averaged BAO distance DV (z 1) increases but DV (z > 1) falls [10] It implies that DR14 may improve the constraint on the total active neutrino mass. We update the constraints on the EOS of DE, the active neutrino masses, the dark radiation and the spatial curvature with the Planck data and the BAO measurements including the DR14 quasar sample at z = 1.52.

Data and methodology

Constraints on dark energy

Constraints on the total mass of active neutrinos

Constraints on the dark radiation

Constraints on the curvature

Summary and discussion