An Unbiased Estimator of Peculiar Velocity with Gaussian Distributed Errors for Precision Cosmology

Abstract

We introduce a new estimator of the peculiar velocity of a galaxy or group of galaxies from redshift and distance estimates. This estimator results in peculiar velocity estimates which are statistically unbiased and that have errors that are Gaussian distributed, thus meeting the assumptions of analyses that rely on individual peculiar velocities. We apply this estimator to the SFI++ and the Cosmicflows-2 catalogs of galaxy distances and, using the fact that peculiar velocity estimates of distant galaxies are error dominated, examine their error distributions, The adoption of the new estimator significantly improves the accuracy and validity of studies of the large-scale peculiar velocity field and eliminates potential systematic biases, thus helping to bring peculiar velocity analysis into the era of precision cosmology. In addition, our method of examining the distribution of velocity errors should provide a useful check of the statistics of large peculiar velocity catalogs, particularly those that are compiled out of data from multiple sources.

arXiv comment6 Pages, 5 Figures

References in corpus (27)

• Cosmicflows-2: The Data
• The density and peculiar velocity fields of nearby galaxies
• Consistently Large Cosmic Flows on Scales of 100 Mpc/h: a Challenge for the Standard LCDM Cosmology
• Cosmic Flows on 100 Mpc/h Scales: Standardized Minimum Variance Bulk Flow, Shear and Octupole Moments
• The 6dF Galaxy Survey: Peculiar Velocity Field and Cosmography
• SFI++ I: A New I-band Tully-Fisher Template, the Cluster Peculiar Velocity Dispersion and H0
• Streaming motions of galaxy clusters within 12000 km/s - V. The peculiar velocity field
• The cosmological bulk flow: consistency with $\Lambda$CDM and $z\approx 0$ constraints on ${\sigma }_8$ and $\gamma$
• The 6dF Galaxy Velocity Survey: Cosmological constraints from the velocity power spectrum
• 3D Velocity and Density Reconstructions of the Local Universe with Cosmicflows-1
• An estimate of Ω_m without priors
• Deriving accurate peculiar velocities (even at high redshift)
• The Local Hole revealed by galaxy counts and redshifts
• Evidence for a low-density Universe from the relative velocities of galaxies
• Shellflow. I. The Convergence of the Velocity Field at 6000 km/s
• 2MTF IV. A bulk flow measurement of the local Universe
• The LCO/Palomar 10,000 km/sec Cluster Survey. I. Properties of the Tully-Fisher Relation
• Current Status Of Velocity Field Surveys: A Consistency Check
• The Calibration of the WISE W1 and W2 Tully-Fisher Relation
• Large-Scale Power Spectrum and Cosmological Parameters from SFI Peculiar Velocities
• Large-scale Cosmic Flows from Cosmicflows-2 Catalog
• Comparison of the ENEAR Peculiar Velocities with the PSCz Gravity Field
• Power Spectrum Shape from Peculiar Velocity Data
• Interpreting New Data on Large Scale Bulk Flows
• Theoretical Expectations for Bulk Flows in Large Scale Surveys
• Bulk Flow and Shear Moments of the SFI++ Survey
• Testing the minimum variance method for estimating large-scale velocity moments

Cited by in corpus (37)

• Cosmicflows-3
• Cosmicflows-4
• Analyzing the Large-Scale Bulk Flow using CosmicFlows4: Increasing Tension with the Standard Cosmological Model
• On the observability of individual Population III stars and their stellar-mass black hole accretion disks through cluster caustic transits
• The 6dF Galaxy Survey: Bulk Flows on $50-70h^{-1}$ Mpc scales
• 2MTF VI. Measuring the velocity power spectrum
• The peculiar velocity field up to $z\sim 0.05$ by forward-modeling Cosmicflows-3 data
• The Redshift Space Momentum Power Spectrum II: measuring the growth rate from the combined 2MTF and 6dFGSv surveys
• The Sloan Digital Sky Survey Peculiar Velocity Catalogue
• Standard Siren Speeds: Improving velocities in gravitational-wave measurements of $H_0$
• Measuring the growth rate of structure with Type IA Supernovae from LSST
• Evaluating bulk flow estimators for CosmicFlows-4 measurements
• An estimation of the Local growth rate from Cosmicflows-3 peculiar velocities
• Target Selection for the DESI Peculiar Velocity Survey
• The Redshift-Space Momentum Power Spectrum I: Optimal Estimation From Peculiar Velocity Surveys
• Velocity-Density Correlations from the cosmicflows-3 Distance Catalog and the 2MASS Redshift Survey
• 2MTF - VII. 2MASS Tully-Fisher survey final data release: distances for 2,062 nearby spiral galaxies
• Cosmicflows-3: Cold Spot Repeller?
• Cosmicflows-4: The Baryonic Tully-Fisher Relation Providing ~10,000 Distances
• Bulk flow and shear in the local Universe: 2MTF and COSMICFLOWS-3
• Using peculiar velocity surveys to constrain the growth rate of structure with the wide-angle effect
• Large-scale motions and growth rate from forward-modelling Tully-Fisher peculiar velocities
• Bulk flow in the combined 2MTF and 6dFGSv surveys
• On the Universality of the Bound-Zone Peculiar Velocity Profile
• Easily Interpretable Bulk Flows: Continuing Tension with the Standard Cosmological Model
• Growth-rate measurement with type-Ia supernovae using ZTF survey simulations
• Constraining cosmology with pairwise velocity estimator
• From Cosmicflows distance moduli to unbiased distances and peculiar velocities
• On methods of estimating cosmological bulk flows
• Cosmic Flow Measurement and Mock Sampling Algorithm of Cosmicflows-4 Tully-Fisher Catalogue
• The Peculiar Velocity Correlation Function
• Gaussianization of peculiar velocities and bulk flow measurement
• Peculiar Velocity Reconstruction From Simulations and Observations Using Deep Learning Algorithms
• Predicting extragalactic distance errors using Bayesian inference in multi-measurement catalogs
• The Relation Between Transverse and Radial Velocity Distributions for Observations of an Isotropic Velocity Field
• Gravitational potential wells and the cosmic bulk flow
• Improved Methods for Estimating Peculiar Velocity Correlation Functions Using Volume Weighting