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More than 15 years after the discovery of fast radio bursts, new research has unraveled the mystery of the origin and depth of this phenomenon in space.
Fast radio bursts, or FRBs, are strong, bright emissions of radio waves ranging from a fraction of a millisecond to several thousand seconds, each producing energy equivalent to the Sun’s annual output.
Recent research suggests that some FRBs come from magnetars, which are neutron stars with very strong magnetic fields. A fast radio blast was found In the Milky Way It is related to magnetars, according to a 2020 study.
But scientists have yet to determine the origin of the cosmic FRB, which is billions of light years away. It is this confusion that has led an international team of scientists to see what can be learned from observations of nearly 1,900 explosions from a fast radioactive blast source outside our own galaxy called FRB 20201124A, according to she studies Published on 21 September in Nature.
The emissions associated with FRB 20201124A occurred for more than 82 hours in 54 days in the spring of 2021, making it one of the strongest fast radio bursts. It is visible through the largest radio telescope in the world: the five hundred meter spherical radio telescope, or FAST.
During the first 36 days, the research team was surprised to see irregular and short-lived differences in the Faraday rotation scale, which measures magnetic field strength and particle density around FRB 20201124A. A larger spin scale means that the magnetic field near the source of the radio blast is stronger, more intense, or both, and a smaller scale means the opposite, Ping Zhang, co-author of the study, said via email. astrophysicist.
“This does not reflect the beginning of the FRB,” said Zhang, founding director of the Center for Astrophysics at the University of Nevada, Las Vegas. “The source of FRB has been there for a long time but is mostly asleep. Sometimes he wakes up (this time for 54 days) and he emits a lot of heartbeats ”.
The scales increased and decreased over that time period, so they stopped for the past 18 days before the FRB eased, “indicating that the strength and / or strength of the magnetic field along the line of sight around the source of the FRB have changed over time, “added Zhang. indicates that the FRB source environment is evolving dynamically, with rapid changes in magnetic field, density or both. ”
“I liken it to shooting a film around the FRB source, and our film reveals a complex and dynamically evolving magnetic environment that has never been imagined before,” Zhang said in a press release.
a physical model Another research team has suggested, based on observations from FRB 20201124A, that the FRB originated in a binary system about 8,480 light-years away containing a magnetar and a star Be, a much hotter and larger star. which orbits faster than the Sun, according to a separate study published Sept. 21 in the journal Nature Communications.
The researchers found that the radioburst’s complex magnetoenvironment was within an astronomical unit (the distance between the Earth and the Sun) from its source.
They also found that the explosion came from a narrow metal-rich spiral galaxy similar in size to the Milky Way, using the 10-meter Keck telescope in Mauna Kea, Hawaii. The source of the radio blast lies between the spiral arms of the galaxy where no significant star formation has occurred, so it’s unlikely the origin was simply a magnetar, according to Nature Study co-author Sobu Dong, a professor at the Kavli Institute. for Astronomy and Astrophysics. at Peking University.
“Such an environment cannot be directly predicted for isolated magnetars,” Zhang said in a news release. “Maybe there’s something else close to the FRB engine, maybe it’s a binary companion.”
The authors say the modeling study should encourage further research on the fast radio burst signal of the Be star / X-ray binary.
“This note takes us back to the drawing board,” Zhang said. “The FRB is far more mysterious than we think. More multi-wavelength observation campaigns are needed to better reveal the nature of these organisms. ”