The GB6 Catalog of Radio Sources

The Green Bank 4.85 GHz (λ ~ 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^ < δ < +75^deg^ was constructed with data from both epochs. Its noise and position errors are nearly a factor of2^1/2^ 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 φ <= 10.5' 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.