Objective prism radial velocities for clusters of galaxies near the South Galactic Pole

Abstract

A project is described which is aimed at determining redshifts for rich clusters of galaxies over a large area of sky near the South Galactic Pole using Cosmos measurements on deep objective prism plates taken with the U.K. Schmidt Telescope. Results obtained in the ESO/SRC field number 349 are presented. Several of the rich clusters seen in the MacGillivray and Dodd (1982) data for this field have peak redshifts in the range z = 0.12-0.13. Examination of five control areas in this field also provides evidence for a higher-than-expected number of galaxies with redshifts in this interval. It is suggested that there is a large-scale structure in this field at the redshift z = 0.12-0.13 consisting of both high-density condensations of galaxies in the form of rich clusters and a dispersed component of galaxies which extends over much of the area.