The Fast Radio Burst repeats like clockwork, astronomers have found.
Fast Radio Bursts—or FRBs—are some of the most enigmatic phenomena discovered in the universe in the last few decades.
In June of this year, researchers at the Jodrell Bank Observatory in Macclesfield, UK, detected a Fast Radio Burst known as FRB 121102 that repeating over a period that lasted a total of 157 days: with 90 days of activity and 67 of silence.
Now, after just over two months, other telescopes detected new radio bursts coming from the same direction; curiously, this proved that FRB 121102 was indeed a repeater, and experts had already estimated it would appear again.
FRB121102 did not disappoint, but it raised many questions as to the nature of its source. FRB’s are transient radio pulse with a length ranging from a fraction of milliseconds to a few milliseconds. What causes them remains one of the greatest astronomical mysteries of our time. Astronomers speculate that FRBs are crated by some high-energy astrophysical processes, but we just don’t know which.
It has been theorized that FRBs could be caused by either rapidly rotating neutron stars, black holes, supermassive black hole mergers, and, last but not least, advanced alien intelligence. However, FRB 121102 has greatly aided in our understanding of the mysterious source behind FRBs.
According to astronomers, this particular repeating FRB originates from a galaxy located some 3 billion light-years away. Observations from the Jodrell Bank Observatory (and a study published in June 2020) suggest that particular FRB could be associated with “the orbital motion of a massive star, a neutron star or a black hole.”
Experts have been looking at the source of FRB for months and predicted it would go off again soon, and they were not wrong. As revealed by Science Alert, this month’s observations detected new bursts from the same location, confirming the theory that the FRB follows a predictable pattern.
The new observations—which were made by different groups of astronomers—, seem to point towards this specific FRB being linked to the orbital motion of a massive star, a neutron star or a black hole, and not aliens as some of us had hoped.
But even though if FRBs are not attributed to aliens, that doesn’t take away the excitement. The mere existence of fast Radio bursts tells us that despite our best knowledge of the universe, there are things out there that can still captivate our interest, imagination, and curiosity.
Although we may be far from fully understanding what causes FRBs, everything we’ve managed to learn from FRB 121102—which was originally discovered by the Arecibo radio telescope in Puerto Rico in 2012—has helped us better understand the possible cause behind these powerful, yet extremely short signals.
FRB 121102 Periodicity revealed
Several groups of astronomers observed FRB 121102 in order to reveal its periodicity. This was revealed based on five year’s worth of data.
Researchers led by Marilyn Cruces of the Max Planck Institute for Radioastronomy spotted as many as thirty-six bursts coming from FRB 121102 from September 2017 to June 2020, revealing a periodicity of 161 days, as revealed by this study uploaded to arXiv.
Researchers from the National Astronomy Observatory of China led by professor Pei Wang also observed FRBV 121102 using the Five-hundred-meter Aperture Spherical Radio Telescope between March and August of this year. Although they didn’t notice and bursts originating from the source from March to late July, on August 17, 2020, they detected as many as 12 bursts from the source which confirms the FRB was in an active phase again, but with a different periodicity compared to that obtained by Cruces’ team.
Prior to astronomers discovering a repeating cycle, astronomer Kaustubh Rajwade from the University of Manchester recorded a series of bursts from FRB 121102, revealing it was one of the most active FDRB’s discovered to date.
By combining the data, Pei Weng and his colleagues obtained a periodicity of ~156.1 days. The data suggest that the active phase of the FRB is set to end sometime between August 31, and September 9, 2020. If the FRB continues emitting bursts actively after these dates, it could either suggest that the periodicity is flawed, that it needs to be further revised, or that the FRB has changed beyond our current understanding. Exciting times!