Mysterious fast radio burst rediscovered in rare group of galaxies

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Astronomers have found one of the most powerful and distant fast radio bursts ever detected for its unusual cosmic home: a rare “bubble-like” galaxy. The unexpected discovery may shed more light on what causes the mysterious radio wave bursts, which have puzzled scientists for years.

The intense signal, named FRB 20220610A, was first detected on June 10, 2022. It traveled 8 billion light years to reach Earth. A light year The distance light travels in one year, or 5.88 trillion miles (9.46 trillion kilometers).

Fast radio bursts, or FRBs, are intense, millisecond-long bursts of radio waves of unknown origin. The first FRB was discovered in 2007, and since then, hundreds of these rapid, cosmic flashes have been detected coming from distant points across the universe.

This particular fast radio burst lasted less than a millisecond, but it was four times more energetic than previously detected FRBs. The eruption released an amount equal to the energetic emissions of our Sun in 30 years. The initial study was published in October.

Many FRBs emit superbright radio waves that last only a few milliseconds at most before fading, making them difficult to observe.

Radio telescopes have proven helpful in tracing the paths of fast cosmic flashes, so researchers used the Australian Square Kilometer Array Pathfinder, or ASKAP, a radio telescope in Western Australia and the European Southern Observatory's Largest Telescope in Chile to pinpoint where the mysterious burst originated. .

These observations led scientists to a giant celestial bubble that was initially thought to be either a single irregular galaxy or a group of three interacting galaxies.

Now, astronomers have used images from the Hubble Space Telescope to reveal that the fast radio burst came from a group of at least seven galaxies, all of which fit within the Milky Way galaxy.

The findings were presented Tuesday at the 243rd meeting of the American Astronomical Society in New Orleans.

According to the researchers, the galaxies in the group appear to be interacting and may even be in the process of merging, which may have triggered the fast radio burst.

“Without Hubble's imaging, it would still be a mystery whether this FRB originated from a monolithic galaxy or some kind of interacting system,” said lead study author Alexa Gordon, a doctoral candidate in the Department of Astronomy at Northwestern University's Weinberg College of Art. and science, in a statement.

“These kinds of environments — these weird ones — are pushing us toward a better understanding of the mystery of FRBs.”

The group of galaxies, known as the Compact Group, is exceptional and “an example of the densest galaxy-scale structures we know,” said Wen-Fai Fang, associate professor of physics and astronomy at Northwestern and Gordon's advisor.

When the galaxies interact, they can trigger bursts of star formation that can be linked to the explosion, Gordon said.

Fast radio bursts have mostly been detected in isolated galaxies, but astronomers have also detected them in globular clusters and, now, a small group, Gordon said.

“We should continue to find more and more of these FRBs, near and far and in all these different kinds of environments,” he said.

Nearly 1,000 fast radio bursts have been detected since their discovery two decades ago, but astronomers are unclear about what causes the bursts.

But many agree that compact objects such as black holes or neutron stars, the dense remnants of exploded stars, may be involved. Magnetas, or highly magnetized starsAccording to recent research, the source may be responsible for fast radio bursts.

Understanding where the fast radio bursts originate will help astronomers learn more about the underlying cause that sends the streaming across the universe.

“Although hundreds of FRB events have been discovered to date, only a fraction of them represent their host galaxies,” study co-author Yuxin Vic Dong said in a statement. “Within that small region, only a few come from dense interstellar environments, but no one has ever seen such a small group. So, its origin is truly rare. Dong is a National Science Foundation Graduate Research Fellow and postdoctoral fellow in astronomy at Fong's lab at Northwestern.

Further insights into fast radio bursts may lead to revelations about the nature of the universe. As the explosions travel through space for billions of years, they interact with cosmic material.

“The radio waves, in particular, are sensitive to any intervening object in the line of sight — from the FRB location to us,” Fang said. “That is, the waves must travel through any cloud of material surrounding the FRB site, through its host galaxy, across the Universe, and finally through the Milky Way. From the time delay in the FRB signal, we can measure the sum of all these contributions.

Astronomers hope to develop more sensitive methods for detecting fast radio bursts in the future, which could lead to detecting them at greater distances, Gordon said.

“We're ultimately trying to answer the questions: What causes them? What are their progenitors, what are their origins? Hubble observations provide a fascinating view of the surprising kinds of environments that lead to these mysterious phenomena,” Fang said.