Astronomers connect 64 telescopes to observe the structure of the universe

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An international team of astronomers has for the first time combined the power of 64 radio telescope antennas to detect the faint signatures of neutral hydrogen gas on cosmological scales.

The feat was achieved using the South Africa-based MeerKAT telescope, a precursor to the world’s largest radio observatory, the SKA Observatory (SKAO), which will probe the universe in unprecedented detail.

A primary 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 achieve this is by looking at the structure of the universe on the largest scales. At these scales, entire galaxies can be thought of as single points, and analyzing their distribution reveals clues about the nature of gravity and mysterious phenomena like dark matter and dark energy.

Radio telescopes are a fantastic instrument for this, as they can detect radiation at 21cm wavelengths generated by neutral hydrogen, the most abundant element in the universe. By analyzing 3D maps of hydrogen spanning millions of light years, we investigated the total distribution of matter in the universe.

SKAO, which is headquartered in Jodrell Bank, Cheshire, is currently under construction. However, there are already pioneering telescopes, such as the MeerKAT, with 64 dishes, to guide your project. Based in the Karoo Desert and operated by the Radio Astronomy Observatory of South Africa (SARAO), MeerKAT will eventually form part of the full SKAO.

MeerKAT and SKAO will primarily function as interferometers, where the antenna array is combined as a giant telescope capable of capturing images of distant objects with high resolution. “However, the interferometer will not be sensitive enough for the largest scales most interesting to cosmologists studying the universe,” explained co-lead author of the new research paper, Steven Cunnington. “So instead, we use the array as a collection of 64 individual telescopes that allows them to map the giant volumes of sky needed for cosmology.”

The single-plate operating mode was conducted by a team at the University of the Western Cape, with several observations already performed with MeerKAT. This ambitious project involves many other institutions on four continents. In new research released on arXiv and submitted for publication, a team that includes Manchester astronomers Cunnington, Laura Wolz and Keith Grainge present the first cosmological detection using this single-dish technique.

The new detection is of a clustering pattern shared between MeerKAT maps and galaxy positions determined by the Anglo-Australian Optical Telescope. As these galaxies are known to map out the general matter of the universe, the strong statistical correlation between the radio maps and the galaxies shows that the MeerKAT telescope is detecting a cosmic structure on a large scale. This is the first time such detection has been done using an array of multiple dishes operating as individual telescopes. The full SKAO will feature this technique and therefore marks an important milestone in the roadmap for the science of cosmology case with SKAO.

“This detection was done with only a small amount of pilot survey data,” Cunnington revealed. “It’s encouraging to imagine what will be achieved as MeerKAT continues to make bigger and bigger observations.”

“For many years I have worked to predict the future capability of SKAO. Getting to a stage where we are developing the tools we will need and demonstrating its success with real data is incredibly exciting. This just marks the beginning of what we hope will be an ongoing showcase of results that advances our understanding of the universe.”

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More information:
Steven Cunnington et al, HI intensity mapping with MeerKAT: cross-correlation power spectrum detection with WiggleZ galaxies, arXiv: 2206.01579 [astro-ph.CO]

Provided by the University of Manchester

Quote: Astronomers link 64 telescopes to observe the structure of the universe (2022, June 20) retrieved June 21, 2022 from

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