Document Type

Article

Publication Date

2001

Publication Title

Monthly Notices of the Royal Astronomical Society

Department

Department of Physics and Astronomy

Abstract

We present a comparison between the peculiar velocity field measured from the ENEAR all-sky Dn−σ catalogue and that derived from the galaxy distribution of the IRAS Point Source Catalog Redshift Survey (PSCz). The analysis is based on a modal expansion of these data in redshift space by means of spherical harmonics and Bessel functions. The effective smoothing scale of the expansion is almost linear with redshift reaching 1500kms−1 at 3000kms−1. The general flow patterns in the filtered ENEAR and PSCz velocity fields agree well within 6000kms−1, assuming a linear biasing relation between the mass and the PSCz galaxies. The comparison allows us to determine the parameter β = Ω0.6 / b, where Ω is the cosmological density parameter and b is the linear biasing factor. A likelihood analysis of the ENEAR and PSCz modes yields β = 0.5 ± 0.1, in good agreement with values obtained from Tully-Fisher surveys.

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