The program of distant radio galaxies at the special astrophysical observatory of Russia

Abstract

Abstract The results of optical identification of a sample of ultra steep spectra (USS) RC-catalogue objects with the help of the 6-m Russian telescope are given. The objects were found in the RATAN-600 “Experiment Cold” and investigated with the VLA for morphology and accurate radio positions (“The Big Trio Project”). The USS sources make up about 10% of all of the 1145 RC-catalogue sources in an area of about 100 square degrees. More than 70% of these USS sources have FR II morphology and can be used for investigations of the early universe. With the help of accumulated information on 232 USS sources with Z > 1 the relations R(Z) (R-visual magnitude), LAS(Z) (LAS-the largest angular size) and spectral index α(Z) were constructed and the mean red shift of our sample sources turns out to be 2. All sources of our sample were separated into groups: compact steep spectra (CSS) with radio dimensions smaller than the size of the optical galaxy, sources with largest angular sizes, sources with bright nucleus, and so on. The list of 32 most evident candidates in distant galaxies is completed. These sources are the first priority sample for very deep spectroscopy.