Peculiar Velocity Decomposition, Redshift Space Distortion and Velocity Reconstruction in Redshift Surveys. II. Dark Matter Velocity Statistics

Abstract

Massive spectroscopic redshift surveys open a promising window to accurately measure peculiar velocity at cosmological distances through redshift space distortion (RSD). In paper I of this series of work we proposed to decompose peculiar velocity into three eigen-modes (v_δ, v_S and v_B) in order to facilitate the RSD modeling and peculiar velocity reconstruction. In the current paper we measure the dark matter RSD related statistics of the velocity eigen-modes through a set of N-body simulations, including the velocity power spectra, correlation functions, one-point probability distribution functions, cumulants and the damping functions describing the Finger of God effect. (1) The power spectrum measurement shows that these velocity components have distinctly different spatial distribution and redshift evolution. In particular, we measure the window function \tilde{W}(k,z), which describes the impact of nonlinear evolution on the v_δ-density relation. We confirm that it can induce a significant systematic error of O(10%) in RSD cosmology. We demonstrate that \tilde{W} can be accurately described by a simple fitting formula with one or two free parameters. (2) The correlation function measurement shows that the correlation length is O(100), O(10) and O(1) Mpc for v_δ, v_S and v_B respectively. These correlation lengths determine where we can treat the velocity fields as spatially uncorrelated. (3) The velocity PDFs and cumulants quantify non-Gaussianities of the velocity fields. We confirm speculation in paper I that v_δis largely Gaussian, nevertheless with non-negligible non-Gaussianity, v_B is significantly non-Gaussian. We also measure the damping functions. Despite the observed non-Gaussianities, the damping functions and hence the FOG effect are all well approximated as Gaussian ones at scales of interest.

21 pages, 17 figures. Accepted by PRD. Equation typos corrected

References in corpus (10)

• A test of the nature of cosmic acceleration using galaxy redshift distortions
• A discriminating probe of gravity at cosmological scales
• Confirmation of general relativity on large scales from weak lensing and galaxy velocities
• Testing cosmological structure formation using redshift-space distortions
• Observational Tests of Modified Gravity
• Generation of Vorticity and Velocity Dispersion by Orbit Crossing
• The dependence of dark halo clustering on the formation epoch and the concentration parameter
• Differentiating dark energy and modified gravity with galaxy redshift surveys
• An ideal mass assignment scheme for measuring the Power Spectrum with FFTs
• Coherent Combination of Baryon Acoustic Oscillation Statistics and Peculiar Velocity Measurements from Redshift Survey

Cited by in corpus (44)

• Fast and accurate mock catalogue generation for low-mass galaxies
• Tests of redshift-space distortions models in configuration space for the analysis of the BOSS final data release
• Peculiar velocities in redshift space: formalism, N-body simulations and perturbation theory
• Accurate fitting functions for peculiar velocity spectra in standard and massive-neutrino cosmologies
• Mapping the real space distributions of galaxies in SDSS DR7: I. Two Point Correlation Functions
• The fully non-linear post-Friedmann frame-dragging vector potential: Magnitude and time evolution from N-body simulations
• Sampling Artifact in Volume Weighted Velocity Measurement.--- I. Theoretical Modelling
• Evolution of mass and velocity filed in comic web: comparison between baryonic and dark matter
• Nonlinear reconstruction of redshift space distortions
• Sampling Artifact in Volume Weighted Velocity Measurement.--- II. Detection in simulations and comparison with theoretical modelling
• Accurate determination of halo velocity bias in simulations and its cosmological implications
• Study on the mapping of dark matter clustering from real space to redshift space
• Helmholtz Decomposition of the Lagrangian Displacement
• Determination of the large scale volume weighted halo velocity bias in simulations
• The Clustering of Galaxies in the Completed SDSS-III Baryon Oscillation Spectroscopic Survey: Cosmic Flows and Cosmic Web from Luminous Red Galaxies
• Bayesian cosmic density field inference from redshift space dark matter maps
• Measurement of Redshift Space Power Spectrum for BOSS galaxies and the Growth Rate at redshift 0.57
• Assessing the accuracy of cosmological parameters estimated from velocity -- density comparisons via simulations
• Tight $H_0$ constraint from galaxy redshfit surveys: combining baryon acoustic osillation measurements and Alcock-Paczynski test
• Bayesian redshift-space distortions correction from galaxy redshift surveys
• Hybrid modeling of redshift space distortions
• Clustering in the Simulated H$\alpha$ Galaxy Redshift Survey from Nancy Grace Roman Space Telescope
• Kriging Interpolating Cosmic Velocity Field
• Sensitivity tests of cosmic velocity fields to massive neutrinos
• Cosmology with extragalactic proper motions: harmonic formalism, estimators, and forecasts
• Kriging interpolating cosmic velocity field. II. Taking anistropies and multistreaming into account
• Nonlinear Reconstruction of the Velocity Field
• Evolution mapping II: describing statistics of the non-linear cosmic velocity field
• Study on the mapping of halo clustering from real space to redshift space
• Quantification of the multi-streaming effect in Redshift Space Distortion
• Modeling galaxy clustering on small scales to tighten constraints on dark energy and modified gravity
• Measuring cosmic filament spin with the kinetic Sunyaev-Zel'dovich effect
• A possible explanation of vanishing halo velocity bias
• Breaking the ${\tau }_{\mathrm{T}}-f$ degeneracy of the kinetic Sunyaev Zel'dovich cosmology in redshift space
• Measuring neutrino mass imprinted on the anisotropic galaxy clustering
• FLAMINGO: Galaxy formation and feedback effects on the gas density and velocity fields
• Lagrangian displacement field estimators in cosmology
• Parameterization of Stochasticity in Galaxy Clustering and Reconstruction of Tomographic Matter Clustering
• Phenomenological power spectrum models for H$\alpha$ emission line galaxies from the Nancy Grace Roman Space Telescope
• Estimating power spectrum of discrete cosmic momentum field with fast Fourier transform
• The mass and redshift dependence of halo star clustering
• Using two point correlation functions to understand the assembly histories of Milky Way-like galaxies
• Improved Methods for Estimating Peculiar Velocity Correlation Functions Using Volume Weighting
• Expansion series of the pairwise velocity generating function and its implications on redshift space distortion modeling