An international team of astronomers has for the first time combined the power of 64 radio telescope antennas to detect faint signs of neutral hydrogen gas on a cosmological scale.
This was made possible by the MeerKAT telescope, located in South Africa. It is the forerunner of the world’s largest radio observatory, the SKA Observatory (SKAO), which will explore the universe in as much detail as possible.
Radio telescopes are a fantastic tool for this, as they can detect radio emissions with a wavelength of 21 cm, generated by neutral hydrogen, the most common element in the universe. By analyzing three-dimensional maps of hydrogen that reach millions of light-years, we can trace the general distribution of matter in the universe.
SKAO is currently under construction. However, pioneering telescopes already exist, such as the MeerKAT 64-beam telescope. Located in the Kara Desert and operated by the South African Radio Astronomical Observatory (SARAO), MeerKAT will eventually become part of SKAO.
MeerKAT and SKAO will work mainly as interferometers, where an array of plates is combined into one giant telescope capable of capturing images of distant objects with high resolution.
Other institutions located on four continents are involved in this ambitious project. In a new study, the team presents the first-ever cosmological discovery using this technique.
The new discovery is a general picture of clustering between MeerKAT maps and the position of galaxies determined by the Anglo-Australian Optical Telescope. Because these galaxies are known to track the total matter of the universe, a strong statistical correlation between radio maps and galaxies shows that the MeerKAT telescope detects a large-scale space structure. This is the first case of detection using a multi-beam array that works as separate telescopes. The entire SKAO system will be based on this technique.