We present a comparison between the peculiar velocity field measured from the ENEAR all-sky D-n-sigma 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 1500 km s(-1) at 3000 km s(-1). The general flow patterns in the filtered ENEAR and PSCz velocity fields agree well within 6000 km s(-1), assuming a linear biasing relation between the mass and the PSCz galaxies. The comparison allows us to determine the parameter beta=Omega (0.6)b, where Omega is the cosmological density parameter and b is the linear biasing factor. A likelihood analysis of the ENEAR and PSCz modes yields beta =0.5 +/-0.1, in good agreement with values obtained from Tully-Fisher surveys.
Nusser, A., da Costa, L.n., Branchini, E.F., Bernardi, M., Alonso, M.v., Wegner, G., et al. (2001). Comparison of the ENEAR peculiar velocities with the PSCz gravity field. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 320(3), L21-L24 [10.1046/j.1365-8711.2001.04107.x].
Comparison of the ENEAR peculiar velocities with the PSCz gravity field
BRANCHINI, ENZO FRANCO;
2001-01-01
Abstract
We present a comparison between the peculiar velocity field measured from the ENEAR all-sky D-n-sigma 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 1500 km s(-1) at 3000 km s(-1). The general flow patterns in the filtered ENEAR and PSCz velocity fields agree well within 6000 km s(-1), assuming a linear biasing relation between the mass and the PSCz galaxies. The comparison allows us to determine the parameter beta=Omega (0.6)b, where Omega is the cosmological density parameter and b is the linear biasing factor. A likelihood analysis of the ENEAR and PSCz modes yields beta =0.5 +/-0.1, in good agreement with values obtained from Tully-Fisher surveys.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
