OMEGA AND BIASING FROM OPTICAL GALAXIES VERSUS POTENT MASS

The mass density held in the local universe, recovered by the POTENT m ethod from peculiar velocities of similar to 3000 galaxies, is compare d with the density field of optically selected galaxies. Both density fields are smoothed with a Gaussian filter of radius 12h(-1) Mpc. Unde r the assumptions of gravitational instability and a linear biasing pa rameter b(o) between optical galaxies and mass, we obtain beta(o) drop Ohm(0.6)/b(o) = 0.74 +/- 0.13. This result is obtained from a regress ion of POTENT mass density on optical density after correcting the mas s density field for systematic biases in the velocity data and POTENT method. The error quoted is just the 1 sigma formal error estimated fr om the observed scatter in the density-density scatterplot; it does no t 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 g oodness of fit, but the scatter about the fit is consistent with our e stimates of the uncertainties.