By John Kessler
Astronomers have ruled out a major explanation for why the unusual cosmic signal FRB 20180916B is repeating itself.
FRB 20180916B is one of the most famous fast radio bursts discovered in 2018. It is located just 500 million light years from us in another galaxy and has a burst pattern that repeats every 16 days: four days of activity and 12 days of calm. This predictability makes it an ideal subject for study.
Several radio sources are repetitive, although most are random. FRB 20180916B is one of two exceptions, it occurs cyclically.
According to existing models, this radio burst was the result of the interaction of two stars that are orbiting closely. But the authors of the new work said that if this were the case, then the lower frequencies and longer radio waves should change under the influence of wind-charged particles surrounding the binary system.
In order to confirm or refute the hypothesis, the authors of the new work used two telescopes for simultaneous observations of FRB – the Low Frequency Array radio telescope (LOFAR) and the Westerbork Synthesis radio telescope.
As a result of their work, they found redder wavelengths in the LOFAR data – meaning that the winds could not have been present and blocked them. Also, this could not be done by other low-frequency absorption or scattering mechanisms.
Now the authors are testing the theory with a magnetar, according to the authors, it can emit such radio signals.