Thanks to a naturally occurring phenomenon in the universe, researchers discover a signal from a record-breakingly distant galaxy.
Montreal – How do stars form in distant galaxies? This question tries the astronomy to be clarified for many years – but it is not easy. The signals that galaxies send out become weaker the farther they are from Earth. It is therefore difficult for current telescopes to pick up these signals and make data available to research.
But now two researchers have made a discovery that could help astronomy. Arnab Chakraborty of Canada’s McGill University and Nirupam Roy of the Indian Institute of Science have used the Giant Metrewave Radio Telescope in India to capture the 21cm line of a distant galaxy. The study by the two researchers was in the journal Monthly Notices of the Royal Astronomical Society released.
Researchers discover signal from a distant galaxy
The 21 cm line is a signal at a very specific wavelength, also known as the hydrogen line. This signal is emitted by neutral hydrogen atoms and makes it possible to learn more about the composition of the galaxy.
“A galaxy emits different types of radio signals. So far, it has only been possible to detect this particular signal from a nearby galaxy, limiting our knowledge to those galaxies closer to Earth,” Chakraborty explains in one Message his university.
Gravity lensing magnified the signal by a factor of 30
The galaxy whose signal the two researchers discovered is particularly exciting for science: SDSSJ0826+5630 is star-forming, which means that new stars are forming there. It is the most distant galaxy where the hydrogen line has been captured so far.
A phenomenon that occurs naturally in space came to the aid of the two researchers: “Thanks to the help of a gravitational lens we were able to capture a weak signal from a record-breaking distance,” says Chakraborty. Co-author Roy explains the phenomenon: “Gravitational lensing magnifies the signal from a distant object, helping us get a glimpse of the early Universe. In this particular case, the presence of another massive body, another galaxy, diffracts the signal between the target and the observer. This effectively magnifies the signal by a factor of 30, allowing the telescope to pick it up,” adds Roy.
His co-author Chakraborty is certain: “This will help us understand how galaxies are composed much further from Earth.”
Galaxy signal lets researchers see 8.8 billion years in the past
The galaxy’s signal that the research team picked up was emitted by the galaxy when the universe was just 4.9 billion years old. Today it is 13.8 billion years old. “That’s equivalent to looking back 8.8 billion years,” explains Chakraborty, who studies cosmology in Canada.
Thanks to the hydrogen line of the distant galaxy, the two researchers have already been able to determine that the atomic mass of the gas content in the galaxy is almost twice the mass of the stars that are visible. Researchers now hope that in the future other distant galaxies can also be observed using gravitational lenses. (tab)
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