High-redshift radio galaxies from the Molonglo Catalogue

Abstract

Radio and optical observations of a sample of southern hemisphere radio galaxies, selected from the 408 MHz Molonglo Reference Catalogue, are discussed. The sample is defined by means of two criteria: flux densities greater than 0.9 Jy and low-frequency spectral indices steeper than -0.9. From the initial sample of 700 sources, 150 combine the best characteristics of the 1 Jy and ultrasteep samples. It is suggested that these sources can be used to find galaxies at large redshift and explore the properties of galaxies at extreme luminosities and early epochs. VLA 6 cm maps and optical identifications of 13 sources are presented. Eleven of the sources have extended optical structures with morphologies characteristic of high-redshift (z greater than 0.8) radio galaxies.