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OMEGA AND BIASING FROM OPTICAL GALAXIES VERSUS POTENT MASS

M. J. Hudson·A. Dekel·S. Courteau·S. M. Faber·J. A. Willick
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Abstract

The mass density field in the local universe, recovered by the POTENT method from peculiar velocities of $\sim$3000 galaxies, is compared with the density field of optically-selected galaxies. Both density fields are smoothed with a Gaussian filter of radius 12 $h^{-1}$ Mpc. Under the assumptions of gravitational instability and a linear biasing parameter $b\sbo$ between optical galaxies and mass, we obtain $β\sbo \equiv \om^{0.6}/b\sbo = 0.74 \pm 0.13$. This result is obtained from a regression of POTENT mass density on optical density after correcting the mass density field for systematic biases in the velocity data and POTENT method. The error quoted is just the $1σ$ formal error estimated from the observed scatter in the density--density scatterplot; it does not include the uncertainty due to cosmic scatter in the mean density or in the biasing relation. We do not attempt a formal analysis of the goodness of fit, but the scatter about the fit is consistent with our estimates of the uncertainties.

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M. J. Hudson, A. Dekel, S. Courteau, S. M. Faber, J. A. Willick. 1995-02-15. OMEGA AND BIASING FROM OPTICAL GALAXIES VERSUS POTENT MASS. https://doi.org/10.1093/mnras%2F274.1.305

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