Probing the nature of dark energy through galaxy redshift surveys with radio telescopes

TL;DR

Radio telescopes, with recent technological advances, are becoming competitive with optical surveys in mapping large-scale galaxy distributions, enabling precise measurements of dark energy's properties over cosmic time.

Contribution

This paper highlights the potential of next-generation radio telescopes, like the SKA, to measure dark energy parameters with precision comparable to optical surveys.

Findings

Radio telescopes can efficiently map large galaxy samples.

Upcoming radio surveys will constrain dark energy parameters.

The SKA will map the universe's matter distribution over 12 billion years.

Abstract

Galaxy redshift surveys using optical telescopes have, in combination with other cosmological probes, enabled precision measurements of the nature of dark energy. We show that radio telescopes are rapidly becoming competitive with optical facilities in spectroscopic surveys of large numbers of galaxies. Two breakthroughs are driving this change. Firstly, individual radio telescopes are more efficient at mapping the sky thanks to the large field-of-view of new phased-array feeds. Secondly, ever more dishes can be correlated in a cost-effective manner with rapid increases in computing power. The next decade will see the coming of age of the 21cm radio wavelength as a cosmological probe as first the Pathfinders then, ultimately, the Square Kilometre Array is constructed. The latter will determine precise 3D positions for a billion galaxies, mapping the distribution of matter in the Universe over the last 12 billion years. This radio telescope will be able to constrain the equation of state of dark energy, and its potential evolution, to a precision rivalling that of future optical facilities such as DESI and Euclid.