Modeling the Anisotropic Two-Point Galaxy Correlation Function on Small Scales and Improved Measurements of H(z), D_A(z), and f(z)sigma_8(z) from the Sloan Digital Sky Survey DR7 Luminous Red Galaxies

TL;DR

This paper introduces a simple, efficient model for the two-point galaxy correlation function on small scales, improving measurements of cosmological parameters from SDSS data by accounting for nonlinear effects and scale-dependent bias.

Contribution

The paper presents a new phenomenological model that accurately describes galaxy clustering down to small scales and enhances the precision of cosmological parameter measurements from galaxy surveys.

Findings

Improved measurements of H(z)r_s(z_d)/c, D_A(z)/r_s(z_d), and f(z)sigma_8(z) at z=0.35.

Model validation using LasDamas mock catalogs shows good agreement.

Potential to tighten dark energy and gravity constraints with current and future data.

Abstract

We present a simple and efficient phenomenological model for the two-dimensional two-point galaxy correlation function that works well over a wide range of scales, from large scales down to scales as small as 25Mpc/h. Our model incorporates nonlinear effects, a scale-dependent galaxy bias on small scales, and allows the redshift-space distortions to be scale and direction dependent. We validate our model using LasDamas mock catalogs, and apply it to the Sloan Digital Sky Survey (SDSS) DR7 Luminous Red Galaxies (LRGs). Using only the monopole and quadrupole of the correlation function measured from the SDSS DR7 LRGs, we obtain improved measurements H(z)r_s(z_d)/c=0.0433\pm 0.0042, D_A(z)/r_s(z_d)=6.59\pm 0.46, and f(z)sigma_8(z)=0.429\pm 0.089 at z=0.35, using the scale range of 25<s<120Mpc/h. We expect our results and model to be useful in tightening dark energy and gravity constraints from the full analysis of current and future galaxy clustering data.