The Square Kilometre Array and 21 cm cosmology

Abstract

Detecting the 21 cm signals of neutral hydrogen atoms is crucial to understanding the physics of the Universe during its first billion years, and can also provide an important cosmological probe to the expansion history of the late universe, the properties of dark matter and dark energy, and the formation and evolution of various structures. The Square Kilometre Array (SKA) is an international big-science project, and it will be the largest radio telescope in the world after its completion of construction. In the forthcoming decades, the SKA will undoubtedly push the 21 cm cosmology into a new era.