Review Article | Published:

Extragalactic radio continuum surveys and the transformation of radio astronomy

Abstract

Next-generation radio surveys are about to transform radio astronomy by discovering and studying tens of millions of previously unknown radio sources. These surveys will provide fresh insights for understanding the evolution of galaxies, measuring the evolution of the cosmic star-formation rate, and rivalling traditional techniques in the measurement of fundamental cosmological parameters. By observing a new volume of observational parameter space, they are also likely to discover unexpected phenomena. This Review traces the evolution of extragalactic radio continuum surveys from the earliest days of radio astronomy to the present, and identifies the challenges that must be overcome to achieve this transformational change.

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Acknowledgements

Some of the information in Supplementary Table 1 was taken from tables kindly shared by H. Andernach117, I. Prandoni and J. Callingham. I thank the following for contributing to or commenting on an early draft of this Review: H. Andernach, J. Callingham, C. Chandler, J. Condon, E. de Blok, R. Ekers, M. Filipovic, C. Hales, G. Heald, N. Hurley-Walker, A. Kimball, R. Kothes, M. Lacy, E. Lenc, T. Muxlow, E. Murphy, T. Oosterloo, I. Prandoni, H. Röttgering, N. Seymour, V. Smolcic, R. Taylor and R. Wayth.

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The author declares no competing financial interests.

Correspondence to Ray P. Norris.

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Fig. 1: Typical sources in the radio sky.
Fig. 2: Number of known extragalactic radio sources detected in surveys as a function of time.
Fig. 3: Sky area versus sensitivity of modern radio surveys.
Fig. 4: The number of radio sources as a function of flux density, plotted as a Euclidean-normalized differential source count plot at 1.4 GHz.