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Astronomers have traced one of the most powerful and farthest fast radio bursts ever detected to this unusual cosmic home: a rare group of “blob-like” galaxies. The unexpected discovery could shed more light on what causes mysterious bursts of radio waves that have baffled scientists for years.
The intense signal, called FRB 20220610A, was first detected on June 10, 2022, and traveled 8 billion light-years to reach Earth. A light year is the distance light travels in one year, or 5.88 trillion miles (9.46 trillion kilometers).
Fast radio bursts, or FRBs, are intense, millisecond bursts of radio waves of unknown origin. The first FRB was discovered in 2007, and since then hundreds of these fast cosmic flashes have been detected coming from distant points of the universe.
This particular fast radio burst lasted less than a millisecond, but was four times more energetic than previously detected FRBs. The eruption released an amount of energy equivalent to our sun’s energy emissions over 30 years, according to an initial study published in October.
Many FRBs emit superluminous radio waves that last for a few milliseconds at most before fading away, making them difficult to observe.
Radio telescopes have been helpful in tracing the paths of fast cosmic flashes; So researchers used the Australian Square Kilometer Array Pathfinder, or ASKAP, radio telescope in Western Australia and the European Southern Observatory’s Very Large Telescope in Chile to determine where the mysterious explosion originated. .
The observations led scientists to a giant celestial blob, which was initially thought to be a single irregular galaxy or a group of three interacting galaxies.
Now, using images from the Hubble Space Telescope, astronomers have revealed that the fast radio burst came from a group of at least seven galaxies so close together that they could all fit inside the Milky Way galaxy.
The findings were presented Tuesday at the 243rd meeting of the American Astronomical Society in New Orleans.
An unusual galactic group
According to the researchers, the galaxies in the group appear to be interacting and may even be in the process of merging; This may have triggered the fast radio burst.
“Without Hubble’s imaging, it would still remain a mystery whether this FRB originates from a monolithic galaxy or some type of interactive system,” said lead study author Alexa Gordon, a doctoral student in astronomy at Northwestern University’s Weinberg College of Arts. and Sciences, in a statement.
“It’s these kinds of environments, these strange environments, that push us to better understand the mystery of FRBs.”
The galactic group, known as a compact group, is extraordinary and “an example of the densest galaxy-scale structures that we know of,” said study co-author Wen-fai Fong, an associate professor of physics and astronomy at Northwestern and Gordon’s advisor.
As galaxies interact, they can trigger bursts of star formation that could be linked to the explosion, Gordon said.
Fast radio bursts have largely been traced to isolated galaxies, but astronomers have also found them in globular clusters and now in a compact group, Gordon said.
“We need to continue to find more of these FRBs, both near and far and in all these different environments,” he said.
Investigating the origins of fast radio bursts
Nearly 1,000 fast radio bursts have been detected since their first discovery nearly two decades ago, but astronomers remain unclear about what causes the bursts.
But many agree that compact objects such as black holes or neutron stars, the dense remnants of exploding stars, are likely involved. Magnetars, or highly magnetized stars, may be the primary cause of fast radio bursts, according to recent research.
Understanding where fast radio bursts originate could help astronomers learn more about the underlying reason they spread across the universe.
“Despite hundreds of FRB events discovered to date, only a small fraction of them have been determined to belong to host galaxies,” Yuxin Vic Dong, one of the authors of the study, said in a statement. “Of such a small fraction, only a few came from the dense galactic environment, but none have ever been seen in such a compact group. So its birthplace is truly rare.” Dong is a National Science Foundation graduate research fellow and a doctoral student in astronomy in Fong’s laboratory at Northwestern.
Learning more about fast radio bursts could also lead to explanations about the nature of the universe. Bursts interact with cosmic material as they travel through space over billions of years.
“Radio waves in particular are sensitive to any interfering material along the line of sight from the FRB location to us,” Fong said. “This means that the waves must pass through any cloud of material around the FRB region, through the host galaxy, through the universe, and finally through the Milky Way. We can measure the sum of all these contributions from the time delay in the FRB signal.”
Gordon said astronomers expect increasingly sensitive methods to detect fast radio bursts, which could lead to the discovery of more at greater distances in the future.
“Ultimately, we’re trying to answer these questions: What causes these things? What are their ancestors and what are their origins? Hubble observations provide a spectacular view of the surprising types of environments that give rise to these mysterious events,” said Fong.
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