The first billion years of the universe

ASTRO 3D astronomers are studying the process by which the structures in the Universe first formed, using low-frequency radio waves.

The Epoch of Reionisation refers to the period in the history of the Universe during which the neutral hydrogen gas was ionised (electrons removed from atoms) and the smooth matter distribution become the highly structured galaxies and clusters of galaxies we have today.

The observational Epoch of Reionisation project explores the first billion years of the Universe, as probed through the redshifted emission line of neutral hydrogen gas. Studying the spatial and temperature distribution of the neutral hydrogen gas between the first galaxies provides key insights into the growth of structure at Cosmic Dawn and the first sources of ionising radiation in the Universe. In ASTRO 3D, we are exploring this signal with the Murchison Widefield Array (MWA), and in future Square Kilometre Array (SKALow), both of which will be located in the remote Western Australian desert.

The MWA EoR project is an international collaboration, with major contributions from ASTRO 3D nodes at the University of Melbourne and Curtin University, and partner institutions CSIRO and the University of Washington. The collaboration has been collecting data from 2013 onwards towards three regions of the sky, and across a wide period in the first billion years of the Universe. The team collect, calibrate, process and analyse these thousands of hours of data to extract the weak cosmological signal from all of the sources of extragalactic, Galactic and terrestrial contamination that blanket it. In ASTRO 3D, the primary science aims are improvements in our signal processing and signal extraction, leading to first detection and exploration of this era. The MWA observational data will be combined with the theoretical predictions of the Genesis Simulations and the processing efficiency aims of the Data Intensive Astronomy thread.