Cosmological Constraints from the Redshift Dependence of the Alcock-Paczynski Effect: Dynamical Dark Energy

Abstract

We perform an anisotropic clustering analysis of 1,133,326 galaxies from the Sloan Digital Sky Survey (SDSS-III) Baryon Oscillation Spectroscopic Survey Data Release 12 covering the redshift range 0.15 < z < 0.69. The geometrical distortions of the galaxy positions, caused by incorrect assumptions in the cosmological model, are captured in the anisotropic two-point correlation function on scales of 6-40 h ^-1 Mpc. The redshift evolution of this anisotropic clustering is used to place constraints on the cosmological parameters. We improve the methodology of Li et al. to enable efficient exploration of high-dimensional cosmological parameter spaces, and apply it to the Chevallier-Polarski-Linder parameterization of dark energy, w = w ₀ + w _a z/(1 + z). In combination with data on the cosmic microwave background, baryon acoustic oscillations, Type Ia supernovae, and H ₀ from Cepheids, we obtain Ω _m = 0.301 ± 0.008, w ₀ = -1.042 ± 0.067, and w _a = -0.07 ± 0.29 (68.3% CL). Adding our new Alcock-Paczynski measurements to the aforementioned results reduces the error bars by ∼30%-40% and improves the dark-energy figure of merit by a factor of ∼2. We check the robustness of the results using realistic mock galaxy catalogs.