Astrophysicists have been puzzling over the nature of the mysterious cosmic signals for 15 years, the sources of which are located billions of light-years from our galaxy. A new study reveals some interesting details about this unusual phenomenon.
Since 2002, scientists have been trying to understand the nature of the mysterious Fast Radio Bursts (FRB) - high-energy pulses of just a few milliseconds that originate from galaxies billions of light-years away from the Milky Way. Although only a handful of such phenomena have been recorded over the past 15 years, new research suggests that fast radio bursts may be one of the main "elements" of space in the visible Universe, occurring about once a second.
What are fast radio bursts
To this day, scientists are still debating what actually causes FRB. The most popular theory is that they are caused by rapidly rotating neutron stars with unusually strong magnetic fields known as magnetars. Of course, some are convinced that radio bursts are the result of the work of huge installations of xenocivilization, which thus searches for other intelligent life forms in the Universe. For a long time, astronomers thought that FRBs appeared as a consequence of cosmic-scale catastrophes, such as supernova explosions. But this hypothesis has been disproved by a study of FRB 121102, an object that produces radio bursts with surprising regularity. Last month, a team of scientistsworking on the Breakthrough Listen Project (a 10-year mission to search for extraterrestrial intelligence) discovered 15 new sources of radio bursts from the aforementioned source. Until now, only 23 FRB sources were known to science, which in itself speaks of the difficulty of detecting these strange signals.
Using data on FRB 121102 and other known FRB sources, Anastasia Fialkov and Avi Loeb of the Harvard-Smithsonian Center for Astrophysics calculated how many FRBs could exist in the observable part of the universe. Their new work has been published in The Astrophysical Journal Letters. In an official press release, Anastasia notes that if the results of the study are true, then space "is replete with radio bursts like paparazzi photographing a celebrity," but instead of light emission, they manifest themselves in the form of radio waves. Scientists proceeded from the hypothesis that FRB 121102 is an object located in a dwarf, metal-poor galaxy about 3 billion light-years away.
FRB 121102: source over three billion light years
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Why did the choice fall on something so vague and distant? The problem is that astronomers had no choice: this object is currently the only source of fast radio bursts, for which the parent galaxy and the distance to the Milky Way have been determined. In addition, according to Loeb, it is "the only repeating FRB source that has recorded hundreds of signals." The radio spectrum of its bursts is concentrated on a characteristic, rather narrow frequency, which helped the researchers to focus on the object.
According to the astronomer, if humanity gets the opportunity to study even a small part of such sources of cosmic signals, it will be able not only to unravel their origin, but also to answer many other questions about space. For example, fast radio bursts can be used to measure the number of free electrons in relation to a source, allowing scientists to measure the density of matter between different galaxies in the universe. In addition, radio bursts can be used to study the history of space: they will make it possible to find out the period when UV radiation from the first stars destroyed the hydrogen atoms left over from the Big Bang, decomposing them into protons and electrons.
Research criticism and its future
Andrew Siemion, director of the Berkeley Research Center, agrees with the conclusion of the new study. He also believes that fast radio bursts will help space exploration in the future. However, it was not without healthy criticism: Emily Petroff, a researcher at the Netherlands Institute of Radio Astronomy (ASTRON), points out that although the work itself makes a significant contribution to modern astronomy, it lacks statistical data. Not all FRB sources can behave like object 121102, so it is too early to put forward any specific theses, even at the level of hypotheses.
Fortunately, with projects like CHIME and SKA, researchers will have the tools they need to gather more information in the near future.
Vasily Makarov