A High Precision Determination of $\Omega_0$
Session 113 -- Early Universe and Cosmic Microwave background
Oral presentation, Thursday, 12, 1995, 10:00am - 11:30am

## [113.03] A High Precision Determination of $\Omega_0$

E.J.Shaya (U. of Maryland), P.J.E.Peebles (Princeton U.), R.B. Tully (IFA)

\def\kms{\ifmmode{\hbox{km s}^{-1}} \else{km s$^{-1}$\ } \fi}

We model deviations from uniform expansion of the universe among galaxies and groups of galaxies in the vicinity of the Local Supercluster ($cz \le 3000$ \kms). The luminosity distribution is defined by 1138 galaxies and groups derived from a database of 3030 galaxies. The trajectories of all 1138 objects are determined by application of a variational principle in which the path is an extrema of the integral of the Lagrangian over time. Paths are constrained by the present day positions in the sky and the redshifts plus the constraint that peculiar velocities at very early times were small compared to Hubble flow. Mass-to-light is assumed constant for all objects within a given run and runs are made for a wide range of mass-to-light ratios and ages of the universe, $t_0$. Contour maps of $\chi^2$ are generated from the mean square differences in model and observed distance moduli for a subset of 300 galaxies with Tully-Fisher measurements of distance. We report tight constraints for $t_o$, $\Omega_0$, the average mass-to-light ratio, and $H_0$.