THE ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES 103:427-432, 1996 April

                        THE GB6 CATALOG OF RADIO SOURCES

                   P. C. GREGORY, W. K. SCOTT, AND K. DOUGLAS
              Physics Department, University of British Columbia,
             Vancouver, BC, V6T 2A6, Canada; gregory@physics.ugc.ca

                                      AND

                                 J. J. CONDON
           National Radio Astronomy Observatory, 520 Edgemont Road,
                   Charlottesville, VA 22903; jcondon@nrao.edu


                                   ABSTRACT

        The Green Bank 4.85 GHz (lambda ~ 6 cm) survey was made with the
     NRAO seven-beam receiver on the (former) 91 m telescope during 1986
     November and 1987 October.  The final set of sky maps covering the
     declination band 0 deg < Dec. < +75 deg was constructed with data
     from both epochs.  Its noise and position errors are nearly a factor
     of 2^(1/2) smaller than in the epoch 1987 maps, from which the 87GB
     catalog of 54,579 sources stronger than S ~ 25 mJy was extracted.
     Therefore, we used the new maps to make the GB6 catalog of 75,162
     discrete sources with angular sizes phi <= 10.5 arcmin and flux
     densities S >= 18 mJy.  This catalog is available in machine-readable
     versions with either B1950 or J2000 positions and as a printed book
     with B1950 positions.  The GB6 weighted differential source counts
     S^(5/2)n(S) between 18 mJy and 7 Jy agree well with evolutionary
     models based on independent data.


     Subject headings: catalogs -- radio continuum: galaxies -- surveys