64 radio antennas detected a large-scale structure during
An international team of astronomers for the first time combined 64 antennas of the MeerKAT radio telescope (South Africa) to search for faint traces of neutral hydrogen in the Universe. The preliminary results of the study are published in a preprint on arXiv.
The scientific work was carried out as part of the project to create the world’s largest radio interferometer Square Kilometer Array (SKA), parts of which will be deployed in Australia, China, India, Europe and South Africa based on existing and not yet built instruments. The purpose of the SKA is to study the evolution of the Universe and the mechanisms of its expansion, as well as the large-scale structure.
Important for studying dark energy and testing general relativity are maps of the distribution of neutral hydrogen, the most abundant substance in the universe, at low and high redshifts. For this, observations are made of weak radiation with a wavelength of 21 centimeters (known as the HI radio link), but foreground flare is a serious obstacle. Removing nearby sources of bright radio emission, radio frequency interference, and thermal noise requires precise calibration, for which the researchers applied the approach of finding correlations with galaxy surveys.
The data were collected from 10.5 hours of observations using MeerKAT L-band receivers over six nights in the frequency range 1015-973 megahertz at a redshift of 0.4 to 0.459.
Scientists have identified a common clustering pattern between MeerKAT maps and galaxy positions determined by the WiggleZ Dark Energy Survey, a large-scale redshift astronomical survey performed with the 3.9-meter Anglo-Australian telescope at the Siding Spring Observatory (Australia). The strong statistical correlation between radio maps and galaxies shows that MeerKAT is capable of detecting large-scale cosmic structures.