Iranian Scientists Probe Distant Galaxies with MeerKAT Telescope
WANA (Aug 05) – In a groundbreaking study, a team of astronomers led by the Institute for Research in Fundamental Sciences (IPM) in Iran, in collaboration with researchers from the Inter-university Institute for Data Intensive Astronomy and the University of Oxford, has analyzed a set of distant galaxies observed using the MeerKAT radio telescope in South Africa.
MeerKAT, a precursor to the world’s largest radio observatory—the Square Kilometre Array (SKA)—has enabled, for the first time, a comparative analysis of the radio spectra, magnetic field strength, and star formation rates in galaxies that existed when the universe was 9 to 12 billion years younger.
One of the most fundamental questions in astrophysics is how galaxies formed and evolved. To answer this, scientists must collect data from galaxies billions of light-years away. Nearly all our knowledge about galaxies comes from the electromagnetic radiation they emit, ranging from radio waves to gamma rays.
While optical observations show that the star formation rate in galaxies began declining after a period known as the “Cosmic Noon” (around 10–11 billion years ago), relying solely on visible light can bias our understanding. Radio waves, which are not hindered by interstellar dust, offer a more accurate glimpse into the distant universe.
Professor Russ Taylor, principal investigator of the MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) project, said: “This was a key reason why we undertook deep radio observations of selected sky regions with the MeerKAT telescope, located 90 kilometers from the town of Carnarvon in South Africa’s Northern Cape province.”
Professor Fatemeh Tabatabaei from IPM, who led the study, noted: “Our previous radio observations of nearby galaxies showed that emissions between 1 and 10 GHz are powerful indicators of star formation rates. Now, with MIGHTEE’s mapping, combined with other radio surveys, we’ve extended our studies to 160 early galaxies from the Cosmic Noon and beyond.”
Dr. Maryam Khademi, a researcher at IPM, added: “Our detailed analysis reveals that the radio spectrum of these galaxies varies with star formation rate, which may have profound implications for understanding early star-forming galaxies.”
Radio emissions between 1 and 10 GHz are primarily due to synchrotron radiation, produced when high-energy electrons (cosmic rays) spiral through interstellar magnetic fields. Normally, these cosmic rays lose more energy in stronger magnetic fields.
However, the observed spectra in early galaxies suggest that these particles may actually gain more energy in galaxies with stronger magnetic fields and higher star formation rates.
This apparent contradiction might be resolved by the presence of magnetic “mirrors” that energize cosmic rays, or by the detachment of these rays from magnetic fields, carried out by galactic winds and outflows.
“Such conditions are likely only if the magnetic fields in these systems are highly tangled and turbulent,” Tabatabaei explained. “A turbulent magnetic field can accelerate cosmic rays to higher energy levels. These particles are then scattered and decoupled from the magnetic field.”
The study concludes that galaxies during the Cosmic Noon may have been surrounded by halos of high-energy cosmic rays, which also explains the observed excess of radio emission relative to infrared radiation.
This pioneering research opens new windows into the early universe, offering deeper insights into the life cycles of galaxies in their formative years.
Iranian Scientists Probe Distant Galaxies with MeerKAT Telescope. Social media/ WANA News Agency
