The Epoch of Galaxy Formation

Abstract

Observations of merging and active galaxies at red shifts less than one suggest that galaxy formation is an ongoing process. Cosmological N·body models and analytiC estimates of the collapse times of large galaxies suggest that the first systems to form .probably did so at redshifts less than 4. The theoretical picture that leads to these estimates of the beginning of the formation epoch may be seriously in error if new observations of high redshift galaxies reveal a pre·existing old stellar population.