Astronomers discover the origin of a powerful and mysterious radio signal

(CNN) — Astronomers have discovered one of the most powerful and distant fast radio bursts ever seen has an unusual cosmic origin: a strange group of “blob” galaxies. The unexpected discovery could shed more light on the causes of the mysterious bursts of radio waves, which have puzzled scientists for years.

The bright 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 of light in one year, or 5.88 trillion miles (9.46 trillion kilometers).

Fast radio bursts (FRBs) are intense bursts of millisecond radio waves of unknown origin. The first FRB was detected in 2007, and since then hundreds of these fast cosmic flashes have been detected from distant points in the universe.

This particular fast radio burst lasted less than a millisecond, but was four times more energetic than previously detected FRBs. According to a preliminary study published in October, the explosion released the equivalent of our Sun’s energy output over 30 years.

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

Radio telescopes have proven useful for tracking the path of fast cosmic flashes, so the researchers used the Australian Square Kilometer Array Pathfinder, or ASKAP, radio telescope in Western Australia and the European Southern Observatory’s Very Large Telescope to determine where the probe was located. There was an explosion.

The observations led scientists to a giant skyspot, which was initially thought to be an 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 that 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 galactic group

According to the researchers, the galaxies in the group appear to be interacting and may even be in the process of merging, which could trigger the rapid radio burst.

“Without Hubble images, it would remain a mystery whether this FRB originated in a monolithic galaxy or in some kind of interacting system,” said Alexa Gordon, lead author of the study and a doctoral student in astronomy in the Faculty of Astronomy. Statement of Arts and Sciences at Northwestern University.

“It’s these kinds of environments—these strange environments—that push us toward a better understanding of the FRB’s mystery.”

The galactic group, known as a compact group, is unusual and “an example of the densest galaxy-scale structures we know of,” said study co-author Wen-Fai Fong, associate professor of physics and astronomy at Northwestern and Gordon’s advisor. .

As the galaxies interact, they can trigger a burst of star formation, which could be related to the explosion, Gordon said.

Fast radio bursts have primarily been detected in isolated galaxies, but astronomers have also detected them in globular clusters and, now, in compact groups, Gordon explains.

“We need to continue to find more FRBs of this type, near and far, and in all these types of environments,” he said.

Investigation of the origin of fast radio bursts

About 1,000 fast radio bursts have been detected since their initial discovery nearly two decades ago, but astronomers are unclear what causes them.

However, many agree that compact objects, such as black holes or neutron stars, are probably the dense remnants of stars that have exploded. According to recent research, magnetars, or highly magnetic stars, may be the cause of rapid radio bursts.

Understanding the origins of fast radio bursts can help astronomers better determine the underlying cause of what sets them off across the universe.

“Although hundreds of FRB events have been detected to date, only a fraction of them have been identified with their host galaxies,” study co-author Yuxin Vic Dong said in a statement. “Of that small fraction, only a few came from the dense galactic atmosphere, but none had ever been found in such a compact group. So, their birthplace is rare indeed.” Dong is a National Science Foundation graduate researcher and doctoral student in astronomy in Fong’s lab at Northwestern.

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

“Radio waves, in particular, are sensitive to any interfering material in the line of sight to us from the FRB location,” Fong said. “That means the waves have to travel through any cloud of material around the FRB site, through its host galaxy, through the Universe, and finally through the Milky Way. Starting with the delay in the FRB signal, we can measure the sum of all these contributions.”

Astronomers envision increasingly sensitive methods for detecting fast radio bursts in the future, which could lead to finding them at greater distances, Gordon said.

“Ultimately, we are trying to answer the questions: What is the cause? Who are their parents and what are their origins? “The Hubble observations provide a stunning view of the surprising types of atmospheres that give rise to these mysterious phenomena,” said Fong.