The strange, bubble-like origin of mysterious, record-breaking radio explosions

The Hubble Space Telescope reveals a strange birthplace of a record-setting explosion.

• The fast radio burst (FRB) is the most powerful and farthest to date
• Astronomers find that fast radio bursts did not originate in a single galaxy but rather in a group of galaxies on their way to a possible merger.

In the summer of 2022, astronomers detected the most powerful fast radio burst (FRB) ever observed. And coming from a site dating back halfway to the great explosionIt was also the most distant known FRB observed to date.

Now, led by astronomers Northwestern University We have identified the birthplace of this extraordinary object, which is truly intriguing.

Using images from NASA's Hubble Space Telescopethe researchers traced the FRB back to its non-existence One Galaxy but at least a group Seven Galaxies. The galaxies in the cluster appear to be interacting with each other, perhaps even on their way to a possible merger. Such clusters of galaxies are rare and may have created the conditions that trigger fast radio bursts.

This unexpected discovery could challenge scientific models of how and what produces FRBs.

A Hubble Space Telescope image of the galaxy hosting an exceptionally fast and powerful radio burst, FRB 20220610A. Hubble's sensitivity and sharpness reveal a compact cluster of multiple galaxies that may be in the process of merging. They existed when the universe was only 5 billion years old. FRB 20220610A was first discovered on June 10, 2022, by the Australian Square Kilometer Array Pathfinder (ASKAP) radio telescope in Western Australia. The European Southern Observatory's Very Large Telescope in Chile confirmed that the fast radio burst came from far away. Image credit: NASA, ESA, STScI, Alexa Gordon (NW)

“Without Hubble imaging, it remains a mystery whether this fast radio burst originated from a single, homogeneous galaxy or from some kind of interacting system,” said Alexa Gordon of Northwestern University, who led the study. “It's these kinds of environments — these exotic environments — that are pushing us toward a better understanding of the mystery of fast radio bursts.”

Gordon presented this research during the 243rd meeting of the American Astronomical Society in New Orleans, Louisiana. “Detecting the most distant fast radio burst environment using the Hubble Space Telescope” on January 9 as part of a session on “High energy phenomena and their origins“.

Gordon is an astronomy graduate student in Northwestern's Weinberg College of Arts and Sciences, where she was advised by study co-author Wen-Fei Fong, an associate professor of physics and astronomy. Fung and Gordon are also members of the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA).

Birth from a bubble?

Fast radio bursts (FRBs) flare up and disappear within milliseconds. They are short, powerful radio bursts that generate more energy in one fast burst than our Sun emits in an entire year. The record-breaking fast radio burst (FRB) (dubbed FRB 20220610A) was even more extreme than its predecessors.

Not only was it four times more active than the closest FRB, it was also the most distant FRB yet discovered. When FRB 20220610A originated, the universe was only 5 billion years old. (For comparison, the universe is now 13.8 billion years old.)

A Hubble Space Telescope image of the galaxy hosting an exceptionally fast and powerful radio burst, FRB 20220610A. Hubble's sensitivity and sharpness reveal a compact cluster of multiple galaxies that may be in the process of merging. They existed when the universe was only 5 billion years old. FRB 20220610A was first discovered on June 10, 2022, by the Australian Square Kilometer Array Pathfinder (ASKAP) radio telescope in Western Australia. The European Southern Observatory's Very Large Telescope in Chile confirmed that the fast radio burst came from far away. Image credit: NASA, ESA, STScI, Alexa Gordon (NW)

In early observations, the explosion appeared to have originated near an unidentified amorphous bubble, which astronomers initially thought was either a single irregular galaxy or a group of three distant galaxies. But, in a new development, clear images taken by Hubble now indicate that the blob may be at least as many as seven galaxies in close proximity to each other. In fact, the galaxies are so close together that they could all fit inside our own galaxy milky way.

“There is some evidence that group members are interacting,” Fong said. “In other words, they could be commercial material or perhaps on their way to merging. These clusters of galaxies (called compact clusters) are incredibly rare environments in the universe and are the densest galactic structures we know of.”

“This interaction could trigger bursts of star formation,” Gordon said. “This may indicate that the ancestor of FRB 20220610A was associated with a fairly recent population of stars, which matches what we have learned from other FRBs.”

“Although hundreds of FRB events have been detected so far, only a small fraction of them have been mapped to their host galaxies,” said study co-author Yuexin (Vic) Dong, an NSF graduate researcher and PhD in astronomy. student in Fung's lab and a member of CIERA. “Within this small fraction, only a few came from the dense galactic environment, but none have been seen in such a compact group. So, their birthplace is truly rare.”

Mysterious explosions

Although astronomers have detected as many as 1,000 fast radio bursts since they were first detected in 2007, the sources behind the blinding flashes remain largely uncertain. While astronomers have not yet reached a consensus on the potential mechanisms behind FRBs, they generally agree that FRBs must involve a compact object, such as an FRB. Black hole or Neutron star.

By revealing the true nature of fast radio bursts, astronomers were able not only to learn about mysterious phenomena, but also to learn about the true nature of the universe itself. When radio waves from fast radio bursts finally meet our telescopes, they will have traveled billions of years from the distant, early universe. During this journey through the universe, they interact with materials along the way.

“Radio waves, in particular, are sensitive to any intervening material along the line of sight — from the FRB location to us,” Fung said. “This means that the waves must travel through any cloud of material around the site of the fast radio burst, through the host galaxy, through the universe, and finally through the Milky Way. Through the time delay in the FRB signal itself, we can measure the sum of all these contributions.”

To further explore FRBs and their origins, astronomers need to discover and study more of them. As the technology continues to become more sensitive, Gordon says more discoveries — and perhaps even the capture of incredibly faint fast radio bursts — are just around the corner.

“With a larger sample of distant FRBs, we can begin to study the evolution of FRBs and their host characteristics by linking them to nearby ones and perhaps even begin to identify more exotic groups,” Dong said.

“In the near future, FRB experiments will increase their sensitivity, leading to an unprecedented rate of FRBs detected at these distances,” Gordon said. “Astronomers will soon learn how unique the environment of this fast radio burst is.”

Reference: “Fast radio burst in a compact galaxy cluster at Z “~1” Written by Alexa C. Gordon, Wen-fai Fong, Sunil Simha, Yuxin Dong, Charles D. Kilpatrick, Adam T. Deller, Stuart D. Ryder, Tarraneh Eftekhari, Marcin Glowacki, Lachlan Marnoch, August R. Muller, Anya E. Nugent, Antonella Palmez, J. Xavier Prochaska, Mark Ravelski, Ryan M. Shannon and Nicholas Tychos, November 17, 2023, Astrophysics > Astrophysics of galaxies.
arXiv:2311.10815

The study was supported by the National Science Foundation (award numbers AST-1909358, AST-2047919 and AST-2308182), the David and Lucile Packard Foundation, the Alfred P. Sloan Foundation, the Research Foundation for the Advancement of Science and NASA (award number GO-17277). Astronomers first discovered FRB 20220610A using the Australian Square Kilometer Array Pathfinder Radio Telescope in Western Australia and then confirmed its origin with the European Southern Observatory. Very large telescope In Chile.