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Introduction

New astronomical surveys almost invariably herald advances in astrophysics. Surveys play a crucial role in identifying new classes of objects, in revealing structure in the Universe, and in expediting studies of individual objects. Each new generation of instrumentation usually warrants a new survey. Hence the ROSAT Sky Survey replaces the HEAO-I Sky Survey, the 2MASS survey (Kleinmann 1992) will replace the AFGRL survey, etc. Since radio telescopes tend to be unique, there are few matched surveys in the northern and southern hemispheres. The only reasonably uniform sky survey in the radio band is the 5 GHz survey carried out at Greenbank and Parkes; it is the best existing radio survey, with a limiting flux density of mJy and positional accuracy of arcmin. Both the relatively high flux density limit and the relatively large positional uncertainty limit the usefulness of this 5 GHz database. With this in mind, the National Radio Astronomy Observatory (NRAO) has decided to utilize the VLA to produce a next generation radio sky survey.


rlw@stsci.edu