Science & Technology

Brightest, most distant radio signal detected till now has a rare source — a group of merging galaxies

A fast radio burst that occurred when the universe was just 5 billion years old was detected in 2022

By Rohini Krishnamurthy
Published: Wednesday 10 January 2024
FRB 20220610A was detected in 2022. Photo: NASA, ESA, STScI, Alexa Gordon (Northwestern)

Scientists have traced the origin of the farthest and most powerful fast radio burst (FRB) to a group of at least seven galaxies that appear to be merging. Such groups of galaxies are rare and possibly led to conditions that triggered the FRB.

Astronomers led by Northwestern University presented the findings at the 243rd meeting of the American Astronomical Society in New Orleans, Louisiana.

FRBs, emitted by extragalactic sources, are transient flashes of radio waves that typically last a few milliseconds. The energy generated in a quick burst is more than what the sun emits in an entire year.

Read more: Fast radio bursts detected in the Milky Way for the first time

The most powerful and distant FRB was first detected in 2022 by the ASKAP radio telescope in Australia. The burst occurred when the universe was just 5 billion years old. 

The sources of FRB are mysterious but researchers speculate that they could be coming from a compact object such as a black hole or neutron star. 

The researchers relied on images from the Hubble Space Telescope to trace the origin of the 2022 FRB, officially known as FRB 20220610A. 

“Without the Hubble’s imaging, it would still remain a mystery as to whether this FRB originated from one monolithic galaxy or some type of interacting system,” Alexa Gordon from Northwestern University, the lead author of the study, said in a statement. 

Previously, scientists thought that FRB 20220610A originated near an amorphous blob. This, they speculated, could be coming from a single, irregular galaxy or a group of three distant galaxies. 

Read more: How 535 new fast radio bursts can help answer deep questions about the universe

But Hubble’s images indicate that the blob might be as many as seven galaxies that are so close that they could all fit inside our own Milky Way galaxy.

“There are some signs that the group members are ‘interacting’,” study co-author Wen-fai Fong, an associate professor of physics and astronomy said in a statement. 

She explained that the galaxies in question could be exchanging materials or possibly on a path to a merger. “These groups of galaxies are incredibly rare environments in the universe and are the densest galaxy-scale structures we know of,” Fong added.

This interaction could trigger bursts of star formation, Gordon explained. “That might indicate that the progenitor of FRB 20220610A is associated with a fairly recent population of stars, which matches what we’ve learned from other FRBs,” the expert added.

Researchers are interested in distant FRBs as they are key to accurately measuring the missing matter of the universe. 

“If we count up the amount of normal matter in the universe — the atoms that we are all made of — we find that more than half of what should be there today is missing,” Ryan Shannon, a professor at the Swinburne University of Technology in Australia, who was involved in the detection, said in a statement.

Read more: ‘WTF?’: Newly discovered ghostly circles in the sky can’t be explained by current theories, and astronomers are excited

“We think that the missing matter is hiding in the space between galaxies, but it may just be so hot and diffuse that it's impossible to see using normal techniques,” the expert said, adding that FRBs can ‘see’ all the electrons.

As researchers detect more such radio signals, they will be able to study the evolution of these bursts. “In the near future, FRB experiments will increase their sensitivity, leading to an unprecedented rate in the number of FRBs detected at these distances,” Gordon said. 

The first FRB was detected in 2007 and close to 1,000 have been discovered so far. The locations of 19 FRBs have been traced as of June 9, 2022, according to an article in The Conversation, a network of nonprofit media outlets.

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