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.

6 Pages, 5 Figures

References in corpus (10)

• 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
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• Deriving accurate peculiar velocities (even at high redshift)
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• Current Status Of Velocity Field Surveys: A Consistency Check
• The Calibration of the WISE W1 and W2 Tully-Fisher Relation
• Large-scale Cosmic Flows from Cosmicflows-2 Catalog
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Cited by in corpus (20)

• Cosmicflows-4
• Analyzing the Large-Scale Bulk Flow using CosmicFlows4: Increasing Tension with the Standard Cosmological Model
• 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
• 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
• 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
• 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
• Growth-rate measurement with type-Ia supernovae using ZTF survey simulations
• From Cosmicflows distance moduli to unbiased distances and peculiar velocities
• Peculiar Velocity Reconstruction From Simulations and Observations Using Deep Learning Algorithms
• Improved Methods for Estimating Peculiar Velocity Correlation Functions Using Volume Weighting