Researchers from Montreal and India have detected a radio signal from a galaxy nearly nine billion light-years away.
According to their findings, the signal would have been emitted when the universe was only 4.9 billion years old – long before our own solar system formed about 4.5 billion years ago.
“This is equivalent to looking back in time 8.8 billion years,” Arnab Chakraborty, co-author of the study and a postdoctoral fellow 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 pick up the most distant signal ever in a specific radio wavelength known as the 21cm line, which was created by hydrogen, giving them a unique view of the early universe .
“A galaxy emits different kinds of radio signals,” said Chakraborty, who studies cosmology in McGill’s physics department. “Until now, it has only been possible to pick up this particular signal from a nearby galaxy, limiting our knowledge to those galaxies closer 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 the galaxy’s hydrogen gas content is almost twice the mass of the stars that are visible to us.
Normally, signals like those from distant galaxies are too weak to be detected with current radio telescopes, which often look like rows of large television satellite dishes.
“But thanks to the help of a natural phenomenon called gravitational lensing, we can pick up a faint signal from a record-breaking distance,” Chakraborty said. “This will help us understand the composition of galaxies at much greater distances from Earth.”
Nirupam Roy is a co-author of the study and an associate professor of physics at the Indian Institute of Science.
“Gravitational lensing magnifies the signal coming from a distant object to help us peer into the early universe,” explained Roy. “In this particular case, the signal is being distorted by the presence of another massive body, another galaxy, between the target and the observer. This effectively increases the signal by a factor of 30, allowing the telescope to pick it up.”
With funding from McGill University and the Indian Institute of Science, the researchers used the Giant Metrewave Radio Telescope, which is an array of 30 maneuverable radio telescope dishes in the western Indian state of Maharashtra. They say their findings show that it is possible to detect similar signals from distant galaxies using gravitational lensing, opening up new possibilities for studying the early universe with existing low-frequency radio telescopes.
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