Monday, 10 February 2020

Scientists Find First Fast Radio Burst That Repeats At Regular Intervals

Somewhere in the universe, a highly energetic Fast Radio Burst (FRB) is blasting outward from an unknown object, bathing the sky in radio waves. Scientists may be one step closer to understanding these mysterious signals. A new study of FRBs has revealed the first of these energetic signals that repeats at regular intervals. That could finally give astronomers the tools they need to characterize these perplexing cosmic occurrences. 

FRBs have been the subject of intense speculation ever since scientists spotted the first one in 2007. These signals last only a millisecond, and the power is minuscule here on Earth — it’s similar to placing a cell phone call from the moon. However, the origins of FRBs are many millions or billions of light years away. Whatever objects produce FRBs release as much energy in that millisecond as the sun does in 80 years. 

The problem with studying FRBs is they seemed at first to be completely random — astronomers didn’t know where to look for FRBs, they just showed up in the data from time to time. In 2018 and 2019, scientists identified several Fast Radio Burst signals that repeated. In fact, some have speculated that all FRBs repeat, but they do so on very long and irregular intervals. That doesn’t help us study them, though. A new analysis from the Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst Project (CHIME/FRB) does help. The team has discovered a repeating source called “FRB 180916.J0158+65” with a unique property. It repeats at regular intervals. 

The team used the CHIME array in British Columbia (see top) to scan for repeating FRBs between September 2018 and October 2019. During that time, it detected signals from FRB 180916.J0158+65 clustered into a four day period that switched off for the following 12 days. Some of those cycles didn’t produce FRBs, but those that did were right in-line with the 16-day period. 

This FRB source is a significant discovery for several reasons, not least of which it repeats at regular intervals. It’s also relatively close at about half a billion light years distant at the edge of a galaxy called SDSS J015800.28+654253.0. Yes, that’s far away in objective terms, but it’s the nearest repeating FRB ever discovered. The repeating nature of this signal could help scientists hypothesize about the nature of the source. Knowing when and where FRBs will occur could also help teams collect more data and finally solve the mystery.

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