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New research has provided clues that galactic magnetars – young pulsars that rotate slower than ordinary pulsars and have the strongest magnetic fields in the universe – located in the vicinity of a black hole, could possibly be the source of the “fast radio. long milliseconds “. burst “, or FRB – high-energy explosions that originate beyond our galaxy but whose exact nature and origin is unknown.
“More than 60 of these surprise broadcasts have been recorded so far,” reports Dennis Overbye for The New York Times. “The only thing astronomers agree on is that these signals are probably not saluting extraterrestrials.”
Origin – “A special place”
“Perhaps the FRBs originated in some dense mass of matter or gas, such as the remains of an exploded star,” says University of Toronto astronomer Cherry Ng of a 2019 study by the Canadian Hydrogen Intensity Mapping Experiment. , or Chime, in British Columbia .. “” Or maybe they arose near black holes in the heart of distant galaxies, “said Ng, who added that the explosion must have come from” a special place “.
“That could mean in some sort of dense cluster like a supernova remnant or close to the central black hole in a galaxy,” Ng said.
“Maybe we should thank our lucky stars, Overbye notes” that we don’t live in a ‘so special place’ in our galaxy. “
The two questions
“There are two main questions regarding the origin of FRBs,” said astrophysicist Bing Zhang at the University of Nevada, Las Vegas, whose team made new observations on the sources of Fast radio burst, or FRB, which have led to a series of groundbreaking discoveries this could finally shed light on the physical mechanism of FRBs, using the five-hundred-meter spherical telescope (FAST) in Guizhou, China.
Unknown phenomena – “Repetition of FRBs formed by events never seen before”
“The first is what are the engines of the FRBs and the second is what is the mechanism for producing FRBs. We have found the answer to the second question, “said Zhang, about the most enigmatic and powerful events in the cosmos. Until now, scientists don’t know what causes them involves an incredible energy, equivalent to the amount released by the Sun in 80 years.
Two competing theories have been proposed to interpret the mechanism of FRBs, UNLV reports: “One theory is that they are similar to gamma-ray bursts (GRBs), the most powerful explosions in the universe. The other theory compares them more to radio pulsars, which are spinning neutron stars that emit bright, coherent radio pulses. GRB-like models predict a non-variable angle of polarization within each burst, while pulsar-like models predict variations in the polarization angle. “
“Signals from a strange star system”: the “heartbeat” of ultra bright flashes
GRB or Pulsar?
The team used the Chinese FAST to observe a repeating FRB source and found 11 bursts from it. Surprisingly, seven of the 11 light bursts showed different polarization angle swings during each burst. The polarization angles not only varied in each burst, but the variation patterns were also different between the bursts.
“Our observations essentially exclude GRB-like models and offer support for pulsar-like models,” said K.-J. Lee of the Kavli Institute for Astronomy and Astrophysics, Peking University and corresponding author of the article.
Four more articles on FRBs were published in Nature on November 4. These include multiple research articles published by the FAST team led by Zhang and collaborators from the National Astronomical Observatories of China and Peking University. Researchers affiliated with the Canadian Hydrogen Intensity Mapping Experiment (CHIME) and the Survey for Transient Astronomical Radio Emission 2 (STARE2) group also collaborated on the publications.
“Something Unexpected is Happening”: Astronomers Tune into the Cosmic Frequency of Fast Radio Burst
“Just as the first document improved our understanding of the mechanism behind FRBs, these documents solved the challenge of their mysterious origin,” explained Zhang.
City-sized neutron stars – “They have the strongest magnetic fields in the universe”
Magnetars are incredibly dense city-sized neutron stars that possess the most powerful magnetic fields in the universe. Magnetars occasionally emit short X-rays or soft gamma-ray bursts through the dissipation of magnetic fields, so they have long been hypothesized as plausible sources for powering FRBs during high-energy flashes.
“New Clues”: The causes of enigmatic Fast Radio Burst (FRB) remain unknown
The first conclusive proof of this came on April 28, 2020, when an extremely bright radio burst was detected by a magnetar located right in our backyard, about 30,000 light years from Earth in the Milky Way. As expected, the FRB was associated with a bright flash of X-rays.
Most of the magnetized objects in the universe
“We now know that so-called magnetars can produce at least some or perhaps all of the FRBs in the universe,” Zhang said.
The event was detected by CHIME and STARE2, two arrays of telescopes with many small radio telescopes suitable for detecting light events from a large area of the sky.
Intriguing discoveries of “non-detection”
Zhang’s team has long used FAST to observe the magnetar source. Unfortunately, when the FRB occurred, FAST was not looking at the source. However, FAST has made some interesting “non-detection” discoveries and reported them in one of the November 4 articles in Nature. During the FAST observation campaign, there were another 29 x-ray flashes emitted by the magnetar. However, none of these explosions were accompanied by a radio blast.
“Our missed detections and detections by the CHIME and STARE2 teams paint a complete picture of FRB-magnetar associations,” said Zhang.
“Thanks to recent observational findings, FRB theories can finally be critically reviewed,” said Zhang. “The production mechanisms of FRBs are significantly reduced. However, many open questions remain. This will be an exciting field for years to come. “
Sources of Nature.com: No pulsed radio emission during a bursting phase of a galactic magnetar “.” The physical mechanisms of fast radio bursts “,” Oscillations of different polarization angles from a repetitive source of fast radio bursts “
The Daily Galaxy, Max Goldberg, via Nature, UNLV, and The New York Times
Image credit, top of page: It’s a NASA image of the Crab Nebula, powered by a highly magnetized, rapidly spinning neutron star called a pulsar, which formed when a massive star ran out of its nuclear fuel and is collapsed. The combination of rapid rotation and a strong magnetic field in the Crab generates an intense electromagnetic field that creates jets of matter and antimatter that travel away from the north and south poles of the pulsar, and an intense wind that flows in an equatorial direction.
The last image of the crab is an X-ray composite of Chandra (blue and white), NASA’s Hubble Space Telescope (purple), and NASA’s Spitzer Space Telescope (pink). The extent of the X-rays in this image is smaller than the others because the highly energetic electrons that emit X-rays radiate their energy faster than the low-energy electrons that emit optical and infrared light.
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