An international team of astronomers has for the first time combined the power of 64 radio telescope plates to detect the weak signatures of hydrogen-neutral hydrogen gas on a cosmological scale.
The feat was achieved with the MeerKAT telescope based in South Africa, a forerunner of the world’s largest radio observatory, the SKA Observatory (SKAO), which will investigate the universe in unprecedented detail.
A major goal of SKAO is to understand the evolution and content of the Universe along with the mechanisms that drive its accelerated expansion. One way to do this is by observing the structure of the universe on the largest scales. At these scales, entire galaxies can be considered as unique points, and analysis of their distribution reveals clues about the nature of gravity and mysterious phenomena such as dark matter and dark energy.
Radio telescopes are a great tool for this, as they can detect radiation at 21 cm wavelengths generated by neutral hydrogen, the most abundant element in the universe. By analyzing 3D hydrogen maps spanning millions of light-years, we probe the total distribution of matter in the Universe.
SKAO, headquartered in Jodrell Bank, Cheshire, is currently under construction. However, there are already search telescopes, such as the 64-plate MeerKAT array, to guide its design. Headquartered in the Karoo Desert and operated by the South African Astronomical Radio Observatory (SARAO), MeerKAT will eventually become part of the full SKAO.
MeerKAT and SKAO will function primarily as interferometers, where the variety of dishes combine like a giant telescope capable of imagining distant objects with high resolution. “However, the interferometer will not be sensitive enough to the larger scales that are more interesting to cosmologists studying the universe.” explained the lead co-author of the new research paper, Steven Cunnington. “Therefore, we use the matrix as a collection of 64 individual telescopes that allow them to map the giant sky volumes needed for cosmology.”
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