A MERLIN and VLBI Survey of Faint Compact Radio Sources

We have selected a field from the VLA FIRST Survey which is typical in all aspects except one: it contains a bright, but extremely compact VLBI calibrator

• J1159+291. 127 unresolved FIRST sources with $S_{FIRST}\ge 10$ mJy lie within ${2.5}^{\circ }$ of this calibrator. $\lambda 6$ cm MERLIN observations with a resolution $\sim 60$ mas detect around half the sources. These detections form the basis of a sample of faint but compact radio sources which are ideally suited to follow-up VLBI observations.