After nearly 20 years of research, scientists are gradually unraveling the mystery of fast radio bursts (FRBs) – short signals that can surpass the energy output of entire galaxies in fractions of a second. Studies hint at neutron stars as the source of these phenomena, but the mechanism of their formation remains a matter of debate. A recent discovery from the Massachusetts Institute of Technology (MIT) sheds light on this problem: scientists have traced the origin of one of the FRBs to a source located 200 million light-years from Earth.
Although fast radio bursts have existed as long as stars, humanity first discovered them in 2007. Since then, thousands of such signals have been recorded by modern instruments, and some of them show periodicity. This narrowed down the possible sources to magnetars – extremely magnetic neutron stars – and possibly black holes.
A break in the study of fast radio bursts came with the launch of the Canadian Hydrogen Intensity Mapping Experiment (CHIME) in 2020. This radio telescope with four large antennas is capable of capturing signals in the FRB frequency range. In 2022, the telescope detected the signal FRB 20221022A, which came from a distant galaxy. The MIT team, led by Kenzie Nimmo, analyzed this data using the phenomenon of scintillation, an effect of filtering a signal through interstellar gas that causes it to twinkle, similar to the way stars twinkle in the sky.
The study found that scintillation can help determine the size of the area where the signal occurs. This was the key to testing the two main hypotheses of FRB formation. The first hypothesis suggests that fast radio bursts arise from shock waves that propagate from a neutron star. The second is that they originate from the star’s magnetic field.
CHIME analysis detected variations in the brightness of the signal, confirming the presence of scintillation. Gas in the signal’s host galaxy probably partially caused this effect, which in turn acted as a natural lens to refine the size of the source. The results showed that the FRB radiation zone is very small, about 10,000 kilometers in diameter. In comparison, if the signal originated from shock waves, this area would be much larger.
The data confirm that the source of fast radio bursts is the magnetic field of a neutron star, although the exact mechanism of their formation remains a mystery. According to Nimmo, the environment around the magnetars contains an enormous amount of energy that is at the edge of physical possibility. This phenomenon is so powerful that we can observe it even across vast cosmic distances.
Despite significant progress, many aspects of the physics of fast radio bursts require further study. However, such research is gradually bringing us closer to unraveling this cosmic phenomenon.
We previously reported on how the most distant fastest radio burst would help weigh the Universe.
According to news.mit.edu
