Multi-Epoch Observations of Survey Sources

Abstract

Five objects mapped as part of a VLBI survey have been re-observed at 5 GHz, and four of them have also been observed at 10 GHz. Three of the objects show no substantial structural variations: an upper limit of 2c can be placed on the apparent relative velocities of the components. One object (0711+356) shows structural variations which are mostly simply described in terms of a superluminal contraction. The remaining object (3C371, 1807+698) shows substantial structural variations which suggest that it probably is a superluminal source. The source 0710+439 is especially interesting as it consists of a central flat-spectrum core component straddled by two compact steep-spectrum components.

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