For several years, astronomers have been questioning what is called the fast radio bursts but their unpredictable nature has hindered our attempts to understand this bizarre phenomenon. This is why an object called FRB 121102 has been of such interest. Whatever this object may be, it triggers fast radio bursts several times. A team of astronomers studying the signals of FRB 121102 has now reported unexpected results. The FRB 121102 signals appear to be “twisted” in a way that indicates an extreme stellar environment .
The first fast radio bursts were identified in 2007, but they were difficult to study. They have been named precisely, you see. A fast radio burst lasts only a millisecond, and they do not repeat themselves. However, FRB 121102, which lies at the heart of a dwarf galaxy about 3 billion light-years away, is the exception that proves the rule. This object emits fast radio bursts into clusters, allowing scientists to collect data in real time and train more instruments on the source.
We already know that fast radio bursts are incredibly energetic – they should be for us to detect them so far. These emissions could be related to supernovae, pulsars (rotating neutron stars) or magnetars (pulsars with strong magnetic fields). FRB 121102 gives scientists the opportunity to learn more about the environment surrounding the radio source, which could help us understand what causes rapid radio bursts. What they found is evidence of an extremely powerful magnetic field .
The team used the Arecibo Observatory (above) in Puerto Rico and the Green Bank Telescope in West Virginia to observe FRB 121102 unleashing a burst. The idea was to measure the polarization (geometric orientation) of the electromagnetic signal, which can be affected by local phenomena. The extraordinary light polarization of FRB 121102 was totally unexpected. Polarization was observed in other fast radio bursts, but it was 500 times more extreme.
The researchers had the feeling of being close to understanding FRB 121102, but now things are less clear. The new data, however, indicate several possible explanations. FRB 121102 can be a pulsar near a supermassive black hole growing. The plasma circling the black hole could crystallize and polarize the light of FRB 121102, but why would a giant black hole be in a dwarf galaxy? Another possibility is FRB 121102 lies in a dense nebula that affects its signal, but then how did it become bright enough for us to see?
There is a lot of work to do before understanding the fast radio bursts. They are hard to catch, but about 10,000 of them appear in the sky every night. Each one brings us a little closer to the solution.