A sample of mJy radio sources at 1.4 GHz in the Lynx and Hercules fields - I. Radio imaging, multicolour photometry and spectroscopy

With the goal of identifying high redshift radio galaxies with FRI classification, here are presented high resolution, wide–field radio observations, near infra–red and optical imaging and multi–object spectroscopy of two fields of the Leiden–Berkeley Deep Survey. These fields, Hercules.1 and Lynx.2, contain a complete sample of 81 radio sources with S1.4GHz > 0.5 mJy within 0.6 square degrees. This sample will form the basis for a study of the population and cosmic evolution of high redshift, low power, FRI radio sources which will be presented in Paper II. Currently, the host galaxy identification fraction is 86% with 11 sources remaining unidentified at a level of r>25.2 mag (Hercules; 4 sources) or r>24.4 mag (Lynx; 7 sources) or K ∼ >20 mag. Spectroscopic redshifts have been determined for 49% of the sample and photometric redshift estimates are presented for the remainder of the sample.