The Evolving Universe

Lister Staveley-Smith
Professor Lister Staveley-Smith Dr Dan Taranu
Theme Leader Theme Scientist

When in the Universe’s time line did the first galaxies form? How have gas, stars and galaxies subsequently evolved over cosmic time? These are two core questions in our understanding of the Universe, for which CAASTRO’s Evolving Universe theme is focused on providing key new insights.

CAASTRO researchers are searching for the faint radio signal from the 'Epoch of Reionisation', the period when stars, galaxies and quasars ionised the entire Universe. We know that a million years after the Big Bang, the Universe was uniformly filled with neutral gas and dark matter. In contrast, 13.7 billion years later, the Universe today is complex and inhomogeneous, and almost all the gas is ionised. The intervening 'Epoch of Reionization' has not yet been observed and is the last major phase transitions in the evolution of the Universe still to be studied or understood.

The CAASTRO team is also performing new surveys to measure the stellar and gaseous composition of many tens of thousands of galaxies, spread all over the sky and covering a huge range of ages and distances. These measurements will not only provide a view of stars and gas in individual galaxies in unprecedented detail, but will span a cosmologically representative volume, thus opening up a completely new parameter space for understanding galaxy evolution. We will use these data to address the role of gas, stars and outflows in galaxy formation and evolution, to track the evolution of star formation over cosmic time, and to study normal galaxies over eight billion years of the Universe’s history.

Watch the theme video profile as presented by Professor Stuart Wyithe. The projects associated with CAASTRO's Evolving Universe research theme include:

BIGHORNS (the Broadband Instrument for the HydrOgen ReionisatioN Signal): Searching for a global signal of the Epoch of Reionisation.
FLASH (First Large Absorption Survey in HI): An ASKAP survey of the neutral gas content of galaxies in the poorly-explored redshift range 0.5 < z < 1.0
MWA Epoch of Reionisation: Looking for a signature of the epoch of reionisation with the MWA.
SAMI (Sydney-AAO Multi-object Integral-field spectrograph): The first massively multiplexed spatially resolved survey of galaxies.
Simulations: State of the art numerical simulations of high redshift galaxy formation.
WALLABY (Widefield ASKAP L-Band Legacy All-sky Blind SurveY) and DINGO (Deep Investigation of Neutral Gas Origins: A wide (WALLABY) and deep (DINGO) survey of neutral atomic hydrogen in around 600,000 galaxies.
Intensity Mapping: A study of the neutral hydrogen content of the Universe using novel techniques.
Radio Galaxy Environments: A study of the impact of super-massive black holes on their host galaxies using continuum surveys from the Square Kilometre Array.