6 Conclusions

We have presented in this paper a new sample of 84 large angular size radio galaxies selected from the NVSS, with total flux density at 1.4 GHz $\ge 100$ mJy and declination above $+60^{\circ}$. The selection has been made using high resolution and sensitive VLA observations at 1.4 and 4.9 GHz, which allowed us to properly map extended structures and to determine the radio core position. We measured new redshifts for 44 radio sources (Paper II).

We have discussed selection effects and limits. Within our selection criteria the final sample is homogeneous and can be used for statistical studies (Paper III).

37 radio sources in our sample have a linear size larger than 1 Mpc, of which 22 are new. Adding to these the sample of GRGs by Schoenmakers (1999) and the compilation of GRGs from literature data by Ishwara-Chandra & Saikia (1999), the number of known GRGs rises to 103, which allows a detailed study of the properties of this poorly-known class of radio sources.

Acknowledgements

This research is supported in part by the Spanish DGICYT (PB97-1164). GG and LF acknowledge the Italian Ministry for University and Research (MURST) for financial support under grant Cofin98-02-32. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.