Consistent β values from density-density and velocity-velocity comparisons

Saleem Zaroubi, Enzo Branchini, Yehuda Hoffman, Luiz N. Da Costa

Research output: Contribution to journalArticlepeer-review


We apply a new algorithm, called the unbiased minimal variance (hereafter UMV) estimator, to reconstruct the cosmic density and peculiar velocity fields in our local Universe from the SEcat catalogue of peculiar velocities comprising both early-(ENEAR) and late-type (SFI) galaxies. The reconstructed fields are compared with those predicted from the IRAS PSCz galaxy redshift survey to constrain the value of β = Ω0.6m/b, where Ωm and b are the mass density and the bias parameters. The comparison of the density and velocity fields is carried out within the same methodological framework, and leads, for the first time, to consistent values of β, yielding β= 0.57+0.11-0.13 and β = 0.51 ± 0.06, respectively. We find that the distribution of the density and velocity residuals, relative to their respective errors, is consistent with a Gaussian distribution with σ ≈ 1, indicating that the density field predicted from the PSCz is an acceptable fit to that deduced from the peculiar velocities of the SEcat galaxies.

Original languageEnglish
Pages (from-to)1234-1246
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
StatePublished - 11 Nov 2002
Externally publishedYes


  • Cosmology: observations
  • Cosmology: theory
  • Galaxies: clusters: general
  • Galaxies: distances and redshifts
  • Large-scale structure of Universe


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