A look into the past.. Capturing a radio signal from the oldest galaxy discovered so far | Sciences

A look into the past.. Capturing a radio signal from the oldest galaxy discovered so far | Sciences
A look into the past.. Capturing a radio signal from the oldest galaxy discovered so far | Sciences
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In their attempt to understand the origins of the universe and how galaxies form, astronomers have long been tracking and studying the signals that ground-based telescopes pick up from space, but the farther away the galaxies are from us, the fainter these signals become and the more difficult it is to capture and distinguish them.

An unprecedented achievement

And now, in an unprecedented achievement, scientists from McGill University in Montreal, Canada, and India have been able to capture a radio signal from the farthest galaxy so far, with a specific wavelength known as the 21-centimeter line, using the Giant Meter Wave radio telescope in India. This is the first time that this type of radio signal has been detected at such a large distance. This achievement was announced in a press release published on the university’s website on January 16.

“A galaxy emits different types of radio signals,” says Arnab Chakraborty, a postdoctoral researcher at McGill University under the supervision of Professor Matt Dobbs. Until now, this signal could only be picked up from a nearby galaxy, which limited our knowledge to galaxies closest to Earth. “But with the help of a naturally occurring phenomenon called gravitational lensing, we have been able to pick up a faint signal from a record distance. This will help us understand the formation of galaxies located at much greater distances from Earth.”

Illustration showing the discovery of a signal from a distant galaxy (Sawada Pardisi – websites)

gravitational lens

Gravitational lensing is the gravitational effect of matter, which is present and distributed between the distant light source and the observer. This material distribution is able to bend the light source as it travels towards the observer, explains co-author Nirupam Roy, associate professor in the Department of Physics at the Indian Institute of Science. ) this phenomenon by saying that gravitational lensing amplifies the signal coming from a distant object to help us look into the early universe.

In this specific case, adds Nirupam Roy, the signal is bent by the presence of another massive object, another galaxy, between the target and the observer, and this effectively amplifies the signal by a factor of 30, allowing the telescope to pick it up.

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And the press release states that – for the first time – the researchers were able to detect a distant signal from a star-forming galaxy known as “SDSSJ0826 + 5630” and measure the composition of its gas. The study has been published in the journal Monthly Notices of the Royal Astronomical Society.

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Image of a radio signal from the galaxy. (Chakraborty and Roy/NCRA-TIFR/GMRT)
Image of the radio signal captured from the galaxy (Chakraborty Wroy/National Center for Radio Astrophysics)

A look into the depths of the past

The statement says that the signal detected by the team was emitted from this galaxy when the universe was only 4.9 billion years old, which could enable researchers to take a look at the secrets of the early universe. billions of years in the past.”

According to the researchers, these results show the feasibility of observing distant galaxies in similar situations using gravitational lensing, and it also opens up new and exciting opportunities to investigate the cosmic evolution of stars and galaxies using current low-frequency radio telescopes.

The Giant Metrewave Radio Telescope was built and operated by the National Center for Radio Astrophysics (NCRA-TIFR), and the research was funded by McGill University and the Indian Institute of Science.

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