Scientists have discovered a new cryptic Fast Radio Burst. The signal comes from a galaxy similar to the Milky Way and has been repeated 2,000 times.
An illustration of the FAST radio telescope capturing the signal. 1 credit
Fast Radio Bursts (FRBs), “Fast Radio Flashes” in our parlance, are among the most fascinating, explosive and mysterious astrophysical phenomena discovered by deep space scientists. These are radio signals with varying frequency and last for a moment – a few milliseconds – during which colossal energy is released, equivalent to that which the Sun emits for an entire year. There are two main types: the simple ones, which are very difficult to study because they are limited to a single isolated event, and the repeated ones, which “pulsate” at certain intervals. Repeating FRBs allowed scientists to make many important discoveries, but the breakthrough did not come until 2020 with the identification of the fast radio burst FRB 200428, the first detected in the Milky Way. Thanks to that, scientists have actually determined its source, a magnetar (a neutron star with a very strong magnetic field) called SGR 1935 + 2154, located 30 thousand light years from Earth. A new FRB emitted by a magnetar has just been discovered, but its characteristics make it particularly cryptic.
The identification of the new fast radio burst, called FRB 20201124A, was an international research team led by Chinese scientists from Nanjing University, who worked closely with colleagues from the National Astronomical Observatories of the Chinese Academy of Sciences, the Kavli Institute of Astronomy and Astrophysics, Beijing University, Department of Astronomy, University of California, Division of Physics, Mathematics and Astronomy, California Institute of Technology (CALTECH), University of Nevada at Las Vegas and other institutes. The researchers, led by Professors Heng Xu, Kejia Lee and Subo Dong, studied the FRB with the colossal 500-meter-diameter FAST radio telescope, located in the heart of Guizhou Province, China.
During an observing window conducted in the spring of 2021, signal FRB 20201124A was repeated 1,863 times over an 82-hour period. Thanks to the data collected, it was possible to identify the galaxy of origin (a barred spiral similar to the Milky Way and rich in metals), its distance to Earth and the source that produces it, the aforementioned magnetar. However, unlike the other repeated signals, FRB 20201124A has a peculiar bias due to an unstable but fluctuating magnetic field of varying strength.
“I would liken this to making a movie of the ambient environment of an FRB source, and our movie revealed a complex, dynamically changing magnetized environment that had never been imagined before,” the professor said in a statement. Bing Zhang, co-author of the study. “Such an environment is not directly intended for an isolated magnetar. Something else could be in the vicinity of the FRB source, perhaps a companion in a binary system,” added the scientist. The experts believe that in the vicinity of the magnetar there would be a hot blue star capable of influencing the magnetic field and therefore changing the polarization of the signal or its orientation in three-dimensional space. The place where the signal was detected is also considered unusual, so the researchers will have to study the collected data in depth to try to reveal all the secrets behind these fascinating phenomena from deep space. Details of the Fast Radio Burst have been published in two papers (here and here) published in the authoritative scientific journal Nature.