A statistical method for determining the cosmological density parameter from the redshifts of a complete sample of galaxies.
Abstract
The distribution of galaxies in space is approximated by their distribution in a 'redshift space' in which their radial coordinate is cz/H. Deviations from a smooth and uniform Hubble expansion, due either to perturbations arising from density fluctuations in the distribution of galaxies or to virial motions in bound groups and clusters, cause characteristic distortions in 'redshift space'. A method of detecting and measuring these distortions (anisotropies) from the relative redshifts and positions on the sky of pairs of galaxies is proposed. An approximate and a more powerful general method of relating these characteristic distortions to their associated density enhancements (and hence the cosmological density parameter) are presented. The limited data presently available are used to illustrate the approximate method, and a very tentative result of about 0.07 is obtained for the density parameter. The data requirements for a strong test of the density parameter using the general method are discussed.
 Publication:

The Astrophysical Journal
 Pub Date:
 February 1977
 DOI:
 10.1086/182362
 Bibcode:
 1977ApJ...212L...3S
 Keywords:

 Cosmology;
 Density Distribution;
 Galaxies;
 Mass Distribution;
 Red Shift;
 Statistical Analysis;
 Galactic Radiation;
 Hubble Diagram;
 Perturbation Theory;
 Probability Distribution Functions;
 Radial Velocity;
 Star Distribution;
 Stellar Luminosity;
 Astrophysics