Radio patrol of the northern Milky Way : a catalog of sources. II.

The paper presents a catalog of 1274 discrete sources detected during a 5 yr, 6 cm, radio-patrol survey of the Galactic plane for variable sources. Approximately 20 percent of the volume of the Galactic disk was repeatedly observed on 16 occasions. The survey is capable of detecting both short-term (few days) and long-term variability. Seventy-five percent of the sources are weaker than 75 mJy, and as a consequence, reliable detection of variability generally required luminosity variations greater than or equal to 50 percent. Thirty-two variable sources and 27 possible variables were detected, of which 64 percent exhibited short-term variability. Two new identifications are proposed for the short-term variables GT 0116 + 622 and GT 2318 + 620, with the transient gamma-ray source Cas gamma-1 and the X-ray source 4U 2316 + 61, respectively. The absence of giant outbursts leads to an upper limit of three on the number of objects in the survey area with radio properties like Cyg X-3. A comparison with previous centimeter variability studies suggest the possible existence of two distinct variability components.