A team of astronomers managed to trace the origin of a rapid radio flash, in a spiral galaxy about 500 million light years from us.

An international team of scientists has precisely identified the origin of some rapid explosions of radio waves, detected as early as 2018, and known as “FRB 180916”. Through the use of the eight telescopes of the European network VLBI (wide range interferometry), researchers have specified the origin of the phenomenon by determining the distance from which they originate, 500 million light years from Earth, in a totally different environment from the source of the other radio, FRB 121102. According to researchers at the Gemini North Telescope, located in Hawaii, FRB 180916 came from a low emission zone in a spiral galaxy similar to the Milky Way, at a distance six times smaller than the other issue, known by the FRB code name 121102.

The emission of FRB 121102, according to the hypothesis, could be located in a surrounding nebula or in a black hole near a spiral arm of the V-shaped galaxy. But if the region where both emissions come from is clear, what Produces remains a mystery. But what is a FRB? It is a fast radio flash, a high-energy astrophysical phenomenon that manifests itself with a radio pulse that lasts a few milliseconds. These are very bright flashes in the radio band that come from regions of the sky outside the Milky Way. Both natural and artificial explanations have been suggested for the origin of the still unknown rapid radio flashes.

Mysterious radio signals from space continue to trap the minds of astronomers around the world. As a mysterious radio signal, or rather a rapid burst of radio (Fast Radio Burst, Frb), whose origin we have finally managed to discover today. To report it in a study that has just been published in Nature was a team of international researchers, according to which this Frb that repeats over time would originate in a different area and much closer to those observed previously, and more precisely in a spiral galaxy, located about 500 million light years from us.

More radio signals arrive from a nearby galaxy

Remember that fast radio flashes are among the strangest mysteries of the Universe. They are powerful extremely short bursts of electromagnetic radiation detected by radio telescopes, which last no more than a few milliseconds maximum and can generate more energy than 500 million soles. Most Frb have so far only been detected once, which makes it extremely difficult to understand their origin and what generates them.

But in recent years we have begun to find repetitive Frbs, that is, they are repeated over time: the first, called Frb 121102, was discovered in a dwarf galaxy about 3 billion light years from us. Last year, in addition, thanks to the Chime experiment in Canada, up to eight new repetitive Frbs were detected (a total of 10 discovered so far), including a radio signal called Frb 180916.J0158 + 65 (abbreviated Frb 180916), that the team of astronomers has now managed to track.

To do this, the team used eight telescopes of the European Very Long Base Interferometry Network to make observations in the direction of Frb 180916. During five hours of monitoring, the researchers were able to track the origin of the signal, a spiral galaxy very similar to Our Milky Way, called SDSS J015800.28 + 654253.0.

An origin, the researchers explain, very different from that of Frb 121102. “The multiple flashes we witnessed in the first repeated Frb discovered, in fact, emerged from very particular and extreme conditions within a dwarf galaxy,” explained astronomer Benito Marcote of Joint Institute for Vlbi Eric.

“This discovery was the first piece of the puzzle, but it also raised more questions than it solved, for example if there was a fundamental difference between repetitive and non-repetitive Frb. Now, we have located the origin of a second repetitive Frb, which questions our previous assumptions about what could be the source of these explosions”

The possible explanations for the enigmatic Frb proposed so far by the scientific community have been neutron stars, black holes, pulsars, a type of star called blitzar or magnetar, variations of the ultra-intense magnetic field of neutron stars. Although this latest research does not yet provide a definitive answer, it may begin to exclude some proposed hypotheses. “We are at the point where a theory has to explain this diversity or we have to start thinking seriously about the presence of different types of sources for Frb,” says co-author Jason Hessels. “If the Frbs are not all the same, but derive from a variety of events, that could explain why they all seem so different.