Study of baryon acoustic oscillations with SDSS DR13 data and measurements of $\Omega_k$ and $\Omega_\textrm{DE}(a)$

TL;DR

This paper measures baryon acoustic oscillations using SDSS DR13 data to constrain cosmological parameters like curvature and dark energy evolution, providing results consistent with a flat universe and constant dark energy density.

Contribution

It introduces independent BAO observables from SDSS DR13 data and uses them to constrain space curvature and dark energy evolution, including new measurements of $ ext{Omega}_k$ and $ ext{Omega}_ ext{DE}(a)$.

Findings

Measured $ ext{Omega}_k = -0.015 \, ext{±} \, 0.030$

Found $ ext{Omega}_ ext{DE} + 2.2 ext{Omega}_k = 0.717 \, ext{±} \, 0.004$

Results are consistent with a flat universe and constant dark energy density.

Abstract

We measure the baryon acoustic oscillation (BAO) observables $\hat{d}_\alpha(z, z_c)$, $\hat{d}_z(z, z_c)$, and $\hat{d}_/(z, z_c)$ as a function of redshift $z$ in the range 0.1 to 0.7 with Sloan Digital Sky Survey (SDSS) data release DR13. These observables are independent and satisfy a consistency relation that provides discrimination against miss-fits due to background fluctuations. From these measurements and the correlation angle $\theta_\textrm{MC}$ of fluctuations of the Cosmic Microwave Background (CMB) we obtain $\Omega_k = -0.015 \pm 0.030$, $\Omega_{\textrm{DE}} + 2.2 \Omega_k = 0.717 \pm 0.004$ and $w_1 = 0.37 \pm 0.61$ for dark energy density allowed to vary as $\Omega_{\textrm{DE}}(a) = \Omega_{\textrm{DE}} [ 1 + w_1 ( 1 - a)]$. We present measurements of $\Omega_{\textrm{DE}}(a)$ at six values of the expansion parameter $a$. Fits with several scenarios and data sets are presented. The data is consistent with space curvature parameter $\Omega_k = 0$ and $\Omega_{\textrm{DE}}(a)$ constant.