The Combined NVSS-FIRST Galaxies (CoNFIG) sample - II. Comparison of space densities in the Fanaroff-Riley dichotomy

This paper focuses on a comparison of the space densities of Fanaroff-Riley type I (FRI) and FRII sources at different epochs, with a particular focus on FRI sources.

First, we present the concluding steps in constructing the Combined NVSS-FIRST Galaxies (CoNFIG) catalogue, including new Very Large Array observations, optical identifications and redshift estimates. The final catalogue consists of 859 sources over four samples (CoNFIG-1, -2, -3 and -4 with flux density limits of S_1.4GHz = 1.3, 0.8, 0.2 and 0.05Jy, respectively). It is 95.7 per cent complete in radio morphology classification and 74.3 per cent of the sources have redshift data.

Combining CoNFIG with complementary samples, the distribution and evolution of FRI and FRII sources are investigated. We find that FRI sources undergo mild evolution and that, at the same radio luminosity, FRI and FRII sources show similar space density enhancements in various redshift ranges, possibly implying a common evolution.