Cosmological constraints from the redshift dependence of the Alcock-Paczynski effect: application to the SDSS-III BOSS DR12 galaxies

TL;DR

This paper uses the redshift dependence of the Alcock-Paczynski effect in galaxy distributions from SDSS-III BOSS DR12 to derive cosmological constraints, providing a complementary method to existing probes.

Contribution

It applies a novel methodology to measure the redshift evolution of anisotropies caused by the AP effect, yielding competitive cosmological parameter constraints.

Findings

Constraints on Ω_m and w consistent with other probes

Method effectively separates AP and RSD effects

Combines well with other cosmological measurements

Abstract

We apply the methodology developed in \cite{Li2014,Li2015} to BOSS DR12 galaxies and derive cosmological constraints from the redshift dependence of the Alcock-Paczynski (AP) effect. The apparent anisotropy in the distribution of observed galaxies arise from two main sources, the redshift-space distortion (RSD) effect due to the galaxy peculiar velocities, and the geometric distortion when incorrect cosmological models are assumed for transforming redshift to comoving distance, known as the AP effect. Anisotropies produced by the RSD effect are, although large, maintaining a nearly uniform magnitude over a large range of redshift, while the degree of anisotropies from the AP effect varies with redshift by much larger magnitude. We split the DR12 galaxies into six redshift bins, measure the 2-point correlation function in each bin, and assess the redshift evolution of anisotropies. We obtain constraints of $\Omega_m=0.290 \pm 0.053,\ \ w = -1.07 \pm 0.15$, which are comparable with the current constraints from other cosmological probes such as type Ia supernovae, cosmic microwave background, and baryon acoustic oscillation (BAO). Combining these cosmological probes with our method yield tight constraints of $ \Omega_m = 0.301 \pm 0.006,\ w=-1.054 \pm 0.025$. Our method is complementary to the other large scale structure probes like BAO and topology. We expect this technique will play an important role in deriving cosmological constraints from large scale structure surveys.