Redshift-Space Distortions with the Halo Occupation Distribution II: Analytic Model

Abstract

We present an analytic model for the galaxy two-point correlation function in redshift space. The model is constructed within the framework of the Halo Occupation Distribution (HOD), which quantifies galaxy bias on linear and non- linear scales. We model one-halo pairwise velocities by assuming that satellite galaxy velocities follow a Gaussian distribution with dispersion proportional to the virial dispersion of the host halo. Two-halo velocity statistics are a combination of virial motions and host halo motions. The velocity distribution function (DF) of halo pairs is a complex function with skewness and kurtosis that vary substantially with scale. Using a series of collisionless N-body simulations, we demonstrate that the shape of this DF is determined primarily by the distribution of local densities around a halo pair, and at fixed density the velocity DF is close to Gaussian and nearly independent of halo mass. We calibrate a model for the conditional probability function of densities around halo pairs on these simulations. With this model, the full shape of the halo velocity DF can be accurately calculated as a function of halo mass, radial separation, angle, and cosmology. The HOD approach to redshift-space distortions utilizes clustering data from linear to non-linear scales to break the standard degeneracies inherent in previous models of redshift-space clustering. The parameters of the occupation function are well constrained by real-space clustering alone, separating constraints on bias and cosmology. We demonstrate the ability of the model to separately constrain Omega_m, sigma_8, and galaxy velocity bias in models that are constructed to have the same value of beta at large scales as well as the same finger-of-god distortions at small scales. [Abridged]

21 pages, submitted to MNRAS

References in corpus (1)

• Halo assembly bias and its effects on galaxy clustering

Cited by in corpus (10)

• Testing cosmological structure formation using redshift-space distortions
• Towards a Concordant Model of Halo Occupation Statistics
• Observational Tests of Modified Gravity
• Clustering of luminous red galaxies I: large scale redshift space distortions
• An analytic model for the bispectrum of galaxies in redshift space
• On the Halo Occupation of Dark Baryons
• Modeling the three-point correlation function
• Complete Treatment of Galaxy Two-Point Statistics: Gravitational Lensing Effects and Redshift-Space Distortions
• Environmental Effects on Real-Space and Redshift-Space Galaxy Clustering
• Luminous Red Galaxy Halo Density Field Reconstruction and Application to Large Scale Structure Measurements