The Co-ordinated Radio and Infrared Survey for High Mass Star Formation (The CORNISH Survey) - I. Survey Design

TL;DR

The CORNISH survey is an high-resolution radio survey of the inner Galactic plane designed to identify ultra-compact HII regions and other astrophysical objects, providing valuable data for understanding star formation and the interstellar medium.

Contribution

This paper presents the design and implementation of the CORNISH survey, a detailed, high-resolution radio continuum survey of the Galactic plane at 5 GHz, with strategies to optimize beam shape and sensitivity.

Findings

Achieved beam elongation less than 1.5 over 75% of the survey area.

Sensitivity around 2 mJy enables distinction between radio loud and quiet sources.

Survey provides a comprehensive dataset for star formation and Galactic structure studies.

Abstract

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.