The radio background: radio-loud galaxies at high and low redshifts

Abstract

The majority of this paper is devoted to discrete radio sources, and their consequences for cosmology. Three main issues are considered: (i) what makes a galaxy radio loud?; (ii) what do we know about how the population of radio-loud galaxies has changed with epoch?; and (iii) what can observations of high-redshift radio galaxies tell us about general questions of galaxy formation and evolution? The main conclusion is that radio galaxies are remarkably ordinary massive ellipticals. The high-redshift examples are generally old and red and do not make good candidates for primaeval galaxies.

(review at the STScI meeting on Extragalactic Backgrounds) 20 pages, plain TeX Edinburgh Astronomy Preprint 15/93. Paper figs on request