A series of signals emitted from a galaxy that is 500 million light-years away is confusing scientists. These are radio waves that reach Earth in a repetitive pattern every 16 days. According to a recent study, this is the first time that astronomers detect a reliable pattern in signals, known as rapid radio bursts or FRB.
Prior to these studies, the pulses that had been recorded seemed to be random in time, but that changed when the Canadian Rapid Radiation Project of the Hydrogen Intensity Mapping Experiment (CHIME / FRB) discovered a repeated pattern.
The source of the new repetitive FRB, known as 180916.J0158 + 65, was observed through the global effort of eight terrestrial telescopes, which determined the location in a galaxy 500 million light years from Earth. A distance that, although it seems distant, is seven times closer than a previous repeated burst detected in 2019 and more than 10 times closer than the non-repeated FRBs that have been traced.
The newly detected FRB sends explosions that last four days before stopping for 12 days and then repeating. The first 28 cycles were observed between September 2018 and October 2019 using the CHIME radio telescope in British Columbia.
“We conclude that this is the first periodicity detected of any kind at a source of FRB,” the study authors said. “The discovery of periodicity of 16.35 days in a repeated FRB source is an important clue to the nature of this object.”
The study published Monday in the journal Nature and its findings were presented at the 235th annual meeting of the American Astronomical Society in Honolulu.
The first burst of rapid tracked repeated radio, FRB 121102, was linked to a small dwarf galaxy containing stars and metals.
“The multiple flashes we witnessed in the first repeated FRB arose from very particular and extreme conditions within a very small [dwarf] galaxy,” said Benito Marcote, lead author of the Joint Institute study for VLBI in Europe, which converts a global network of telescopes in a single observatory. “Now, we have located a second repeated FRB, which challenges our previous ideas about what could be the source of these explosions.”
On June 19, 2019, the joint institute tuned in to the rapid and repeated radio burst, which was initially discovered by the Canadian CHIME telescope in 2018. For five hours, the telescopes detected four bursts that lasted less than two thousandths of a second.
This new burst of repeated rapid radio not only differs from the repeated one scanned, but of all the rapid radio bursts that have been tracked.
“The differences between repeated and non-repeated rapid radio bursts are therefore less clear, and we believe that these events may not be linked to a particular type of galaxy or environment,” said Kenzie Nimmo, co-author of the study and student of PhD at the University of Amsterdam. “It may be that FRBs occur in a large zoo of locations across the universe and only require some specific conditions to be visible.”
Multiple individual rapid radio bursts have been traced in recent years to their sources in other galaxies, although what created them is still unknown.