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Astronomers trace origin of powerful and mysterious radio signal

(CNN) — Astronomers have tracked one of the most powerful and distant fast radio bursts ever detected to its unusual cosmic origin: a group of strange “blob” galaxies. The unexpected discovery may provide more clues as to the cause of mysterious radio bursts that have baffled scientists for years.

The strong signal, named FRB 20220610A, was first discovered on June 10, 2022, and traveled 8 billion light-years to reach Earth. A light year is the distance that light travels in one year, or 5.88 trillion miles (9.46 trillion kilometers).

Fast radio bursts (FRBs) are powerful bursts of millisecond radio waves of unknown origin. The first FRB was discovered in 2007, and since then hundreds of these rapid cosmic flashes have been detected in distant locations across the universe.

This particular fast radio burst lasted less than a millisecond but was four times more energetic than previously detected fast radio bursts. The explosion released as much energy as the sun has released in 30 years, according to a preliminary study published in October.

Many FRBs emit ultra-bright radio waves that last a few milliseconds at most before disappearing, making them difficult to observe.

Radio telescopes have proven useful in tracking the paths of fast cosmic flashes, so researchers used the Australian Square Kilometer Array Pathfinder (ASKAP), a radio telescope in Western Australia and the European Southern Observatory’s Very Large Telescope in Chile, to identify the mysterious The location of the cosmic flash. An explosion occurs.

These observations led scientists to discover a large black spot in the sky, which was initially thought to be an irregular galaxy or a group of three interacting galaxies.

Now, using images from the Hubble Space Telescope, astronomers have revealed that fast radio bursts come from a group of at least seven galaxies so close together that they could all fit within the Milky Way.

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

An unusual group of galaxies

Researchers say galaxies in the group appear to be interacting and may even be in the process of merging, which could trigger fast radio bursts.

“Without Hubble images, it remains a mystery whether this FRB originated from an overall galaxy or some type of interacting system,” Alexa Gordon, the study’s lead author and an astronomy doctoral student in the Department of Astronomy, said in a report at Northwestern University. Statement from the College of Arts and Sciences.

“It’s these types of environments – these strange environments – that push us to better understand the mysteries of fast radio bursts.”

The cluster, known as a compact galaxy cluster, is special and an example of “the densest galaxy-scale structure we know of,” said study co-author Wenhui Fang, associate professor of physics and astronomy at Northwestern University and Gordon’s adviser. ..

When galaxies interact, they can trigger bursts of star formation, which could be linked to bursts, Gordon said.

Gordon explained that fast radio bursts are mostly found in isolated galaxies, but astronomers have also discovered them in globular star clusters and now in a compact cluster of galaxies.

“We need to continue to find more of these types of fast radio bursts in all these types of environments, both near and far,” he said.

Research on the Origin of Fast Radio Bursts

Nearly 1,000 fast radio bursts have been detected since their first discovery nearly two decades ago, but astronomers still don’t know what causes them.

However, many people believe that dense objects, such as black holes or neutron stars, may be the dense remnants of exploding stars. According to recent research, magnetars, or highly magnetized stars, may be responsible for fast radio bursts.

Understanding the origins of fast radio bursts can help astronomers better determine the underlying causes that launch them into the universe.

“Although hundreds of FRB events have been discovered to date, only a small fraction of them have been identified as their host galaxies,” study co-author Yuxin Vic Dong said in a statement. “Of this small fraction, only a few From a dense galactic environment, but never seen in such a compact group. So, his birthplace is indeed rare.” Dong is a National Science Foundation Graduate Fellow and a doctoral student in astronomy at Northwestern University’s Fang Laboratory .

Better understanding of fast radio bursts could also lead to revelations about the nature of the universe. As bursts travel through space for billions of years, they interact with cosmic matter.

“Radio waves are particularly sensitive to any interfering material along the line of sight (from the FRB location to us),” Fang said. “This means the waves have to pass through any cloud of material surrounding the FRB site, through its host galaxy, through universe, and finally across the Milky Way. Starting from the delay in the FRB signal, we can measure the contribution of the sum of all of these.”

Gordon said astronomers expect increasingly sensitive methods to detect fast radio bursts in the future, which could lead to the discovery of more radio bursts at greater distances.

“Ultimately, we are trying to answer these questions: What causes them? Who are their parents? What is their origin? The Hubble observations provide spectacular insights into the surprising types of environments that trigger these mysterious events,” said Fang. vision. “

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