The Co-ordinated Radio and Infrared Survey for High Mass Star Formation
  (The CORNISH Survey) - I. Survey Design
  We describe the motivation, design and implementation of the CORNISH survey,
an arcsecond resolution radio continuum survey of the inner Galactic plane at 5
GHz using the Karl G. Jansky Very Large Array (VLA). It is a blind survey
co-ordinated with the northern Spitzer GLIMPSE I region covering 10 deg < l <
65 deg and |b| < 1 deg at similar resolution. We discuss in detail the strategy
that we employed to control the shape of the synthesised beam across this
survey that covers a wide range of fairly low declinations. Two snapshots
separated by 4 hours in hour angle kept the beam elongation to less that 1.5
over 75% of the survey area and less than 2 over 98% of the survey. The prime
scientific motivation is to provide an unbiased survey for ultra-compact HII
regions to study this key phase in massive star formation. A sensitivity around
2 mJy will allow the automatic distinction between radio loud and quiet mid-IR
sources found in the Spitzer surveys. This survey has many legacy applications
beyond star formation including evolved stars, active stars and binaries, and
extragalactic sources. The CORNISH survey for compact ionized sources
complements other Galactic plane surveys that target diffuse and non-thermal
sources as well as atomic and molecular phases to build up a complete picture
of the ISM in the Galaxy.
