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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 South Africa’s MeerKAT telescope, 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 most interesting large-scale scales for cosmologists studying the universe,” said Steven Cunnington, lead co-author of the new research paper. “Therefore, we use the array as a collection of 64 individual telescopes that allow them to map the giant sky volumes needed for cosmology.”
The single-mode mode of operation has been driven by a team from Western Cape University, with several observations already made with MeerKAT. This ambitious project involves many other institutions from four continents. In the new research published in arXiv and presented for publication, a team that includes astronomers Cunnington, Laura Wolz and Keith Grainge of Manchester, presents the first cosmological detection using this single-plate technique.
The new detection is a clustering pattern shared between MeerKAT maps and the positions of galaxies determined by the Anglo-Australian optical telescope. Because these galaxies are known to trace the global matter of the universe, the strong statistical correlation between radio maps and galaxies shows that the MeerKAT telescope is detecting a large-scale cosmic structure. This is the first time such a detection has been made using a multiplatform array that functions as individual telescopes. The full SKAO will be based on this technique and therefore this marks an important milestone in the roadmap for the case of the science of cosmology with the SKAO.
“This detection was done with only a small amount of data from the pilot survey,” Cunnington revealed. “It’s encouraging to imagine what will be achieved as MeerKAT continues to make growing observations.”
“For many years I have been working to predict the future capacity of SKAO. Reaching a stage where we are developing the tools we will need and proving its success with real data is incredibly exciting. It only marks the beginning of what we expect. it will be a continuous display of results that advance our understanding of the universe. ”
Astronomers detect galactic space laser More information: Steven Cunnington et al, HI intensity mapping with MeerKAT: power spectrum detection in cross-correlation with WiggleZ galaxies, arXiv: 2206.01579 [astro-ph.CO]arxiv.org/abs/2206.01579 Provided by the University of Manchester
Citation: Astronomers link 64 telescopes to observe the structure of the universe (2022, June 20) retrieved June 20, 2022
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