Researchers from Montreal and India have detected a radio signal coming from a galaxy located nearly nine billion light-years away.
According to their findings, the signal was emitted when the universe was just 4.9 billion years old – long before our own solar system was formed around 4.5 billion years ago.
“That’s the equivalent of going back in time 8.8 billion years,” Arnab Chakraborty, study co-author and postdoctoral researcher at McGill University, said in a press release. .
Published in the journal Monthly Notices of the Royal Astronomical Society, the study explains how researchers were able to capture the most distant signal ever recorded in a specific radio wavelength known as the 21 centimeter line, which is created by hydrogen, giving them a unique insight. of the early universe.
“A galaxy emits different types of radio signals,” said Chakraborty, who studies cosmology in McGill’s physics department. “So far, it has only been possible to capture this particular signal from a nearby galaxy, limiting our knowledge to the galaxies closest to Earth.”
The distant star-forming galaxy is known as SDSSJ0826+5630. The signal also allowed the researchers to determine that the atomic mass of hydrogen gas contained in the galaxy is almost twice the mass of the stars visible to us.
Normally, such signals from distant galaxies are too faint to be detected with today’s radio telescopes, which often look like rows of large television satellite dishes.
“But with the help of a natural phenomenon called gravitational lensing, we can capture a faint signal at record distance,” Chakraborty said. “It will help us understand the composition of galaxies at much greater distances from Earth.”
Nirupam Roy is co-author of the study and associate professor of physics at the Indian Institute of Science.
“The gravitational lens amplifies the signal coming from a distant object to help us peer into the early universe,” Roy explained. “In this specific case, the signal is distorted by the presence of another massive body, another galaxy, between the target and the observer. This effectively results in a magnification of the signal by a factor of 30, allowing the telescope to capture it.”
With funding from McGill University and the Indian Institute of Science, researchers used the giant Metrewave radio telescope, which is an array of 30 maneuverable satellite dishes in the western Indian state of Maharashtra. . They say their findings demonstrate that it is possible to detect similar signals from distant galaxies using gravitational lensing, opening new opportunities to study the early universe with existing low-frequency radio telescopes.
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