Modelling the anisotropic two-point galaxy correlation function on small scales and single-probe measurements of H(z), DA(z) and f(z) 8(z) from the Sloan Digital Sky Survey DR7 luminous red galaxies

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.