The rapid radio burst are already mysterious in themselves. They are even more confusing when they are repeated. Astronomers have just announced the discovery of FRB 180814.J0422 + 73, a recurring rapid radio burst, the second in history. Twelve point signals were also detected. Not bad for a start: the Chime radio telescope, which recorded these bursts, undoubtedly lives up to all expectations.
The hunt for fast radio bursts, cosmic flashes whose origin is still mysterious, is bearing fruit. Astronomers say they have detected 13 new signals, one that is repeated, using the radio telescope CHIME (Canadian Hydrogen Intensity Mapping Experiment). This is only the second recurring fast radio burst ever recorded, since the discovery of FRB 121102 by the Arecibo radio telescope a few years ago.
The bursts quick radio or FRB (Fast radio bursts) are short pulses of radio waves, very energetic but also very short: they last only a few milliseconds. Since their existence has been highlighted in 2007, sixty bursts were detected, all punctual. These phenomena seem to originate far from the Milky Way and they emit in one millisecond as much energy as the Sun in 10,000 years. Their nature, meanwhile, remains an enigma.
Origins still unknown
Most theories about their origin evoke cataclysmic events resulting in the destruction of their source like the explosion of a star giving a supernova, a fusion of neutron stars. It has also been suggested that these signals are issued by advanced extraterrestrial civilizations, but this is another story. These theories began to waver when, in 2015, a succession of fast radio bursts with the same origin (FRB 121102) was recorded by the powerful Arecibo radio telescope, located on the island of Puerto Rico – note that FRB 121102 was observed for the first time in 2012 and that other occurrence were detected a few years later.
Astronomers are driving the nail today by announcing the detection of a new signal that repeats itself. Called FRB 180814.J0422 + 73, the fast radio burst seems to originate about 1.5 billion light-years from Earth. The source could be “a dense cluster, like a supernova remnant, or a point near the central black hole of a galaxy,” says Cherry Ng of the University of Toronto, one of the astronomers involved in this discovery.
1,000 more radio bursts at the end of the year?
The detection of FRB 180814.J0422 + 73 and the other twelve specific FRBs, which is the subject of two studies published in the prestigious journal Nature (here and here), is one of the first results of the Chime radio telescope, located in British Columbia in Canada and inaugurated at the end of 2017. The signals were detected in just three weeks of observation between July and August 2018, while the telescope was not yet operating at full capacity. In all, six repetitions were recorded from the source FRB 180814.J0422 + 73, which was studied a little longer than the one-off FRB, until October.
For the fifty scientists in the Canadian collaboration behind this detection, this second series of rapid radio bursts suggests that there may be others. “With the daily mapping of the northern hemisphere by Chime, we will surely find more successions of bursts over time,” said Ingrid Stairs, of the University of British Columbia, in a statement.
“By the end of the year, we may have found another 1,000 bursts,” said Deborah Good of the same university. After all, astronomers estimate that it could occur up to 10,000 FRB per day and expect that Chime will be able to detect between 2 and 50 each day.
Multiplying the observations of these signals will put your finger on the nature of their source. “It is not yet clear whether the sources that generate repetitive FRBs are different from those that seem to generate only one. It is possible that what we think are now sporadic FRBs are repeated only very rarely but that they come from the same type of sources,” says Shriharsh Tendulkar of McGill University in Montreal, co-author of the study.
If the origin of these flashes of radio waves is still poorly known, for the researcher, it is “extremely unlikely” that they are issued by extraterrestrial civilizations.
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