Statistically complete samples of extragalactic radio sources, providing as much as possible information about their physical and geometrical parameters, radio structure and morphology, optical and X-ray counterparts, etc., are still of great importance for further astrophysical and cosmological studies. The best studied samples, complete within a defined sky area and flux-limited only, were selected from finding surveys of the sky carried out at a number of frequencies. In particular, much observational attention have been given to the brightest sources at 178 MHz (10-Jy sample: Laing et al. 1983, and references therein), 408 MHz (B3-VLA sample: Vigotti et al. 1989), 2.7 GHz (2-Jy sample: Wall & Peacock 1985; cf. also Morganti et al. 1993; Tadhunter et al. 1993), and 5 GHz (S5 sample: Kühr et al. 1981; 1.3-Jy sample: Pearson & Readhead 1988; CJ1 0.7-Jy sample: Polatidis et al. 1995).
A similar effort has been undertaken at 1.4 GHz. About 240 intermediate-strength radio sources stronger than 0.55 Jy and located within a sky area of 0.44 sr were selected by Machalski & Maslowski (1982) (hereafter referred to as Paper I) from the GB and GB2 finding surveys, and afterwards supplemented with those having and , respectively, in two smaller regions corresponding the area of 0.09 sr (Machalski & Condon 1983b). The sample sources were then observed with the VLA at 1465 MHz or 1490 MHz in its partial (P) or A-configuration. High-resolution (1.3-2.5 arcsec) maps were provided for all the sources (Machalski et al. 1982; Paper II, Machalski & Condon 1983a,b; Papers III and IV, respectively). Strongly resolved and/or confused sources were reobserved with the VLA C-array, providing low-resolution maps (Machalski & Condon 1985a; Paper V). As a result, the radio structure, angular size, asymmetry, bending, etc. could be determined for the extended sources. As expected, the sample consists of a large fraction of compact sources, unresolved with the VLA synthesized beam of about 1.2-1.3 arcsec; those were analysed by Machalski & Inoue (1990).
The described VLA observations showed that several GB and GB2 radio sources were strongly confused by a fainter companion closer than about 6-7 arcmin, or even appeared to be a cluster of a few nearby sources unresolved with the arcmin beam of the NRAO 91 m telescope used in the finding surveys. Furthermore, the information content of the sample concerning optical identification, photometry, redshift, X-ray counterpart, etc., has grown since the above publications due to our own observational efforts, as well as results published by other authors investigating objects common with the GB/GB2 sample.
The present paper concludes the sample revising its completeness to the limiting flux of 0.2 Jy, and providing a compendium of the radio, optical, and X-ray parameters for the sample sources. In Sect. 2 a definition of the sample is given, and its completeness is estimated. Designation of the radio spectrum, morphology, and variability is given in Sect. 3, while the optical identification with galaxies and quasars, their magnitudes and redshift, are verified in Sect. 4. The radio, optical, and recent X-ray data for the sample sources are summarized in Sect. 5. Some statistical results: radio morphology and optical identification contents of the sample, revised 1.4-GHz source counts around their peak at about 0.6 Jy, precise spectral-index distributions, and redshift distributions, are described in Sect. 6.