English

Large-scale Cosmic Flows from Cosmicflows-2 Catalog

Cosmology and Nongalactic Astrophysics 2015-06-22 v2

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 Λ\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.

Keywords

Cite

@article{arxiv.1407.6940,
  title  = {Large-scale Cosmic Flows from Cosmicflows-2 Catalog},
  author = {Richard Watkins and Hume A. Feldman},
  journal= {arXiv preprint arXiv:1407.6940},
  year   = {2015}
}

Comments

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

R2 v1 2026-06-22T05:13:21.816Z