Superluminal variations in 3C 120, 3C 273, and 3C 345

The superluminal behavior of 3C 120, 3C 273, and 3C 345 has been reexamined in light of new hybrid maps of these objects. The maps of 3C 273 and 3C 345 are consistent with superluminal expansion. 3C 120 appeared to expand superluminally from 1972.6 to 1974.5, but the evidence has been inconclusive since 1974.5. It is suggested that the jetlike structure of these sources can be explained by a model in which all the components are approaching at a small angle to the line of sight. There is a range of ejection velocities for which components separate superluminally but still maintain comparable intensities