The Square Kilometer Array Observatory (SKAO) will soon be the largest radio telescope in the world. Construction on the array began this year and will take approximately eight years. It will consist of thousands of small radio antennas spread over a distance of thousands of miles to simulate one giant radio telescope. This array will allow astronomers to obtain extremely high sensitivity and angular resolution. Additionally, the array is designed to be able to survey the sky extremely quickly.
The SKAO will help to shed light on essential topics in astronomy and astrophysics, in order to find answers to some of the biggest remaining questions and mysteries in the Universe. The goals of the telescope are wide and varied, and include: investigating the formation structures in the early universe, the formation of the first stars and galaxies, galaxy evolution, and more!
The SKAO observatory will be built in both South Africa and Western Australia. The telescopes will cover two different frequency (or wavelength) ranges, and are thus named to reflect these regimes. SKA-Mid will be an array of 197 traditional dish antennas in South Africa, where SKA-Low will be an array of 131,072 small, tree-like antennas in Western Australia. The arrays will be spread across large distances to achieve high angular resolutions. In South Africa, the most distant antennas will be separated by 150 kilometers, and 65 kilometers in Australia.
A recent study published in the Monthly Notices of the Royal Astronomical Society demonstrates that the SKAO is capable of detecting radio emission from normal spiral galaxies in the early Universe. The authors of the study are part of the “Extragalactic Continuum” working group, which is looking to find a way to study the cosmic era in which star-forming activity suddenly decreased. In the study, the team of scientists simulated the physical properties of the interstellar medium of galaxies at various redshifts (redshift is synonymous with distance or age since the beginning of the Universe. The interstellar medium consists of gas and dust at various temperatures and exists between stars.
In order to understand the transition period between high and low rates of star formation, astronomers need to be able to understand the physical processes that are occurring between galaxies at any given time. Observations of the radio continuum emission trace these processes. The SKAO will be able to map these processes in galaxies at low and high redshifts with high sensitivity.
The team was able to simulate the radio continuum emission from the interstellar medium of typical high redshift galaxies, using well-known galaxies as templates. They were able to show that the SKAO will be sensitive enough to detect galaxies at high redshift in as early as its first deployment stage!