Clusters of Galaxies with Very Large Redshifts

Abstract

There are a number of ways by which the deceleration parameter q_o can be estimated. By assuming objects are bound and by studying gravitational motions one can measure the total mass, both seen and unseen, in galaxies, groups of galaxies, clusters of galaxies or perhaps even in superclusters. Each of these methods at best measures the mass within the particular system and this may not give a true picture of the total mass in the universe. The only way to measure the total mass in a substantial volume of the universe is to use the Hubble relation to determine q_o.