A 2% Distance to z = 0.35 by Reconstructing Baryon Acoustic Oscillations - III : Cosmological Measurements and Interpretation

TL;DR

This paper combines BAO, CMB, supernovae, and local Hubble data to precisely measure cosmological parameters, confirming a flat universe with a cosmological constant and robust H_0 and Omega_m estimates.

Contribution

It provides improved measurements of key cosmological parameters using reconstructed BAO data combined with multiple datasets, and explores model robustness and effects of relativistic particles.

Findings

H_0 = 69.8 +/- 1.2 km/s/Mpc

Omega_m = 0.280 +/- 0.014

w = -0.97 +/- 0.17

Abstract

We use the 2% distance measurement from our reconstructed baryon acoustic oscillations (BAOs) signature using the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) Luminous Red Galaxies (LRGs) from Padmanabhan et al. (2012) and Xu et al. (2012) combined with cosmic microwave background (CMB) data from Wilkinson Microwave Anisotropy Probe (WMAP7) to measure parameters for various cosmological models. We find a 1.7% measurement of H_0 = 69.8 +/- 1.2 km/s/Mpc and a 5.0% measurement of Omega_m = 0.280 +/- 0.014 for a flat Universe with a cosmological constant. These measurements of H_0 and Omega_m are robust against a range of underlying models for the expansion history. We measure the dark energy equation of state parameter w = -0.97 +/- 0.17, which is consistent with a cosmological constant. If curvature is allowed to vary, we find that the Universe is consistent with a flat geometry (Omega_K = -0.004 +/- 0.005). We also use a combination of the 6 Degree Field Galaxy Survey BAO data, WiggleZ Dark Energy Survey data, Type Ia supernovae (SN) data, and a local measurement of the Hubble constant to explore cosmological models with more parameters. Finally, we explore the effect of varying the energy density of relativistic particles on the measurement of H_0.