A High Precision Determination of $\Omega_0$
**Previous
abstract** **Next
abstract**

**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 $H_0$.

**Thursday
program listing**