Abstract:
The distribution of radio continuum galaxies in the sky is a useful, fast, and accessible probe of the distribution of matter in the Universe, covering more than 12 billion years of cosmic history. Through the statistical analysis of this distribution, we can learn about the initial conditions, the physics of dark matter, and the nature of dark energy. However, since radio continuum galaxies are observed through synchrotron emission, they cannot easily be localised in the radial direction, and cross-identification sources from wide surveys are still low. Therefore, we need to analyse the underlying three-dimensional distribution using a tomographic approach by measuring angular cross-correlations. The theoretical predictions of these projected correlations depend on a number of unknown functions relating to the radio galaxy populations that all need to be modelled accurately in order to make reliable inferences about fundamental physics such as the number density of radio continuum galaxies n(z) and radio galaxy bias b(z). In the talk, I will show the latest cosmological results from SKA Observatory (SKAO) pathfinders such as the Evolutionary Map of the Universe (EMU) galaxies and the prospects for future continuum surveys with SKAO in terms of cosmology and extragalactic astrophysics.