Magnetar SGR 1935+2154 Structure, Glitch May Be Among Reasons for Unexplainable Fast Radio Bursts [Study]
A burst of radio waves from deep space had left researchers baffled. The fast radio bursts can release so much energy in a fraction of a second, which makes scientists wonder what caused them.
Fast Radio Bursts
In a new study, scientists observed a quick radio explosion inside the galaxy using two NASA X-ray telescopes. They were able to uncover additional hints on the cause of rapid radio bursts.
The energy explosion originated from a magnetar, an uncommon kind of neutron star. Magnetars are a unique type of neutron star that have extraordinarily strong magnetic fields that are trillions of times stronger than the Earth's magnetic field and billions of times stronger than the typical neutron star. Neutron stars are the extremely dense core that remains after a massive star explodes in a supernova. Thus, only about 30 of these magnetars have been identified yet.
The magnetar known as SGR 1935+2154, a 12-mile-across object located around 30,000 light years distant, was the source of the rapid radio burst reported in the paper. It was previously observed to generate a fast radio burst in 2020. The 2020 burst marked the first instance of a rapid radio burst observed within our own galaxy; all prior observations took place in other galaxies, which were too distant for astronomers to determine their source.
This quick radio burst release mechanism of magnetar SGR 1935+2154 is further elucidated in the current publication. Using NASA's NICER (Neutron Star Interior Composition Explorer) on the International Space Station and NuSTAR (Nuclear Spectroscopic Telescope Array), the researchers saw the burst and reported what transpired on the magnetar's surface and its surroundings.
Magnetar's Structure, Glitches and Fast Radio Bursts
Although the precise cause of the rapid radio burst is yet unknown, experts believe that the magnetar's structure may have some bearing. Under the extreme pressure of the magnetar's gravity, the object's solid surface smashes the interior into a superfluid substance.
The rapid slowing down that occurs as the fluid escapes into space could be caused by massive volumes of energy crashing into the side of the exterior of the two spin out of rhythm, much like water sloshing in a bowl.
Even with this new finding, the exact cause of a quick radio burst remains unknown.
"I think we still need a lot more data to complete the mystery," author George Younes, a researcher at Goddard and a member of the NICER science team, said in a NASA statement.
The rapid radio burst was recorded in between two "glitches," which were abrupt accelerations of the magnetar's rotation. The magnetar typically rotates at a rate of 3.2 times per second, or 7,000 miles per hour. Thus, any change in speed requires a significant amount of energy. Remarkably, after nine hours, between the glitches, it slowed down to its initial speed-a hundred times quicker than anything that has ever been observed in a magnetar.
According to co-author Chin-Ping Hu, an astrophysicist from Taiwan's National Changhua University of Education, malfunctions usually cause the magnetar to slow down for weeks or months until it resumes its regular speed.
It is evident that these objects are undergoing events on far shorter timescales than previously believed, which may have something to do with how quickly radio bursts are produced. They also discovered that the magnetar had begun to emit strong gamma and X-rays prior to the 2022 rapid radio burst.
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