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

TL;DR

This paper refines cosmological parameter constraints using Planck 2015 data combined with the DR14 quasar sample from BOSS, confirming the $ ext{Lambda}$CDM model and providing bounds on dark energy, neutrino masses, and spatial curvature.

Contribution

It incorporates the new DR14 quasar data into cosmological analysis, updating constraints on extended $ ext{Lambda}$CDM models with improved precision.

Findings

The $ ext{Lambda}$CDM model is preferred over extensions.

Dark energy equation of state is close to -1 with small uncertainty.

Upper bounds on neutrino masses are tightened.

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 based six-parameter $\Lambda$CDM model is preferred. Exploring some extensions to the $\Lambda$CDM models, we find that the equation of state of dark energy reads $w=-1.036\pm 0.056$ in the $w$CDM model, the effective 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 $\Omega_k=(1.8\pm1.9)\times 10^{-3}$ 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 $\Delta\chi^2\equiv \chi^2_\text{NH}-\chi^2_\text{IH}=-1.25$.