Astronomers Pinpoint Source of Multiple Cosmic Radio Bursts

Thursday, 03 March 2016 - 2:45PM
Astrophysics
Thursday, 03 March 2016 - 2:45PM
Astronomers Pinpoint Source of Multiple Cosmic Radio Bursts
Scientists are getting closer and closer to discovering the nature of those mysterious fast radio bursts (FRBs) that occasionally ping Earth from outer space. After researchers discovered the exact location of one of the bursts last week for the first time, another team of researchers has now discovered a source of multiple fast radio bursts, shedding some much-needed light on the nature of the phenomenon.

Over the years, various astronomers have detected short bursts of radio waves from an unknown source in the cosmos. Until now, the detected signals were always one-time events, and there was no evidence that another radio burst was ever emitted from the same source. As a result, prevailing theories of the nature of the bursts always involved an explosive or otherwise self-destructing source, such as a supernova or a neutron star collapsing into a black hole. Now, a team of researchers from McGill University has found that several FRBs likely came from the same location, which completely shifts the paradigm of our understanding of the nature of these radio bursts.

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"The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events," the authors wrote in their paper, published in Nature. "Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102, [which] demonstrates that its source survives the energetic events that cause the bursts."
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For this study, the researchers analyzed observations of FRBs from the Arecibo Laboratory, and found that newly discovered bursts from May and June matched the dispersion measures and the sky positions of a burst detected in 2012, called FRB 121102. They definitely came from outside the Milky Way, as their plasma dispersion was ten times what we would expect from a burst that came from within our own galaxy, but otherwise the source remains a mystery.

At the very least, the origin of the bursts can no longer be considered to be an explosive one, or at least not always. There is a chance that the majority of the bursts we've identified in the past were, indeed, one-offs, and that these represent a different type of cosmic radio burst altogether. 

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"Not only did these bursts repeat, but their brightness and spectra also differ from those of other FRBs," lead author Laura Spitler told Phys.org.
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The researchers believe that these repeated pulses may belong to a new sub-class of FRBs, one that has a more exotic origin. They speculate that the source may be an object of unprecedented power that has the capability to emit extremely bright pulses that could be detected on an extragalactic planet. 

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"These repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star," the researchers wrote.
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