Large-scale Cosmic Flows from Cosmicflows-2 Catalog

Abstract

The Cosmicflows-2 catalogue is a compendium of peculiar velocity measurements. While it has many objects in common with the COMPOSITE catalogue, a previously analysed collection of peculiar velocity data found to give an unexpectedly large bulk flow on large scales, the data in Cosmicflows-2 have been reanalysed to ensure consistency between distances measured using different methods. In particular, a focus on accurate distances led the authors of the Cosmicflows-2 to not correct for homogeneous or inhomogeneous Malmquist bias, both or which are corrected for in the COMPOSITE compilation. We find remarkable agreement between the COMPOSITE and the Cosmicflows-2 if the small EFAR sample of clusters located in two dense superclusters is removed from both surveys, giving results that are inconsistent with the $\Lambda$ cold dark matter standard model with Planck central parameters at the 98\% level. On smaller scales we find overall agreement between data sets and consistency with the standard model.

10 pages, 4 figures, 2 tables. Major changes since v1, updated to match version accepted by MNRAS

References in corpus (8)

• Reconstructed Density and Velocity Fields from the 2MASS Redshift Survey
• SFI++ I: A New I-band Tully-Fisher Template, the Cluster Peculiar Velocity Dispersion and H0
• SFI++ II: A New I-band Tully-Fisher Catalog, Derivation of Peculiar Velocities and Dataset Properties
• The peculiar velocity field: constraining the tilt of the Universe
• 2MTF IV. A bulk flow measurement of the local Universe
• Current Status Of Velocity Field Surveys: A Consistency Check
• Power Spectrum Shape from Peculiar Velocity Data
• Bulk Flow and Shear Moments of the SFI++ Survey

Cited by in corpus (3)

• An Unbiased Estimator of Peculiar Velocity with Gaussian Distributed Errors for Precision Cosmology
• Sampling Artifact in Volume Weighted Velocity Measurement.--- II. Detection in simulations and comparison with theoretical modelling
• Determination of the large scale volume weighted halo velocity bias in simulations