Cosmology with SKA Radio Continuum Surveys

TL;DR

The SKA radio continuum surveys will significantly advance cosmology by enabling large-scale tests of non-Gaussianity, isotropy, and systematics, transforming radio observations into a key cosmological tool.

Contribution

This paper summarizes the potential of SKA radio continuum surveys to address major cosmological questions and highlights their unique capabilities in constraining non-Gaussianity and testing isotropy.

Findings

SKA can constrain non-Gaussianity parameter to σ(f_NL) ~ 1.

SKA surveys will help test the isotropy of the Universe at redshift ~1.

Radio continuum surveys will become central in cosmological research.

Abstract

Radio continuum surveys have, in the past, been of restricted use in cosmology. Most studies have concentrated on cross-correlations with the cosmic microwave background to detect the integrated Sachs-Wolfe effect, due to the large sky areas that can be surveyed. As we move into the SKA era, radio continuum surveys will have sufficient source density and sky area to play a major role in cosmology on the largest scales. In this chapter we summarise the experiments that can be carried out with the SKA as it is built up through the coming decade. We show that the SKA can play a unique role in constraining the non-Gaussianity parameter to \sigma(f_NL) ~ 1, and provide a unique handle on the systematics that inhibit weak lensing surveys. The SKA will also provide the necessary data to test the isotropy of the Universe at redshifts of order unity and thus evaluate the robustness of the cosmological principle.Thus, SKA continuum surveys will turn radio observations into a central probe of cosmological research in the coming decades.