Researchers led by a team at McGill University have discovered “the probable source” of the mysterious fast radio bursts (FRBs).
FRBs are transient pulses of radio wavelengths lasting anywhere from a fraction of a millisecond to three seconds long, but it has been difficult to track down their source or understand more about their origins.
Using Canada’s own CHIME telescope (Canadian Hydrogen Intensity Mapping Experiment) at the Dominion Radio Astrophysical Observatory near Pencticton, researchers now have a likely source for FRBs.
A paper published January 1 in Nature titled “A pulsar-like polarization angle swing from a nearby fast radio burst” points to neutron stars as the probable source. Neutron stars are “the ultra-dense remnants of massive stars that have exploded in a supernova.”
“This result reaffirms long-held suspicions about the connection between FRBs and neutron stars,” said Ryan Mckinven, a doctoral researcher in McGill’s Department of Physics and corresponding author of the study published in Nature. “However, our findings also challenge popular theoretical models, providing evidence that the radio emission occurs significantly closer to the neutron star than previously thought.”
In releasing the paper, McGill University stated in a press release that “FRBs release as much energy in milliseconds as the sun emits in an entire day. Scientists have detected thousands of these bursts since their discovery in 2007, yet their origins and mechanisms remain elusive. Mckinven’s study, conducted using the Canadian Hydrogen Intensity Mapping Experiment (CHIME) radio telescope, identified a striking similarity between the behaviour of the FRB signal and that of pulsars, a well-studied class of radio-emitting neutron stars. “
They added “FRB signals are often highly polarized, meaning that the radio waves predominantly oscillate along a specific, well-defined direction. By examining the polarization of the FRB signal, Mckinven’s team observed dramatic changes in its angle over the burst’s 2.5-millisecond duration, a characteristic typical of pulsars but rare in FRBs. This distinctive feature initially raised the possibility that the signal might be from a misclassified pulsar within the Milky Way. However, further analysis confirmed the FRB originated in a galaxy millions of light-years away.”
Published in the same issue of Nature is another paper by Kenzie Nimmo of the Massachusetts Institute of Technology that supports the findings.
Nimmo said, “We discovered that this FRB exhibits ‘twinkling,’ similar to how stars appear to twinkle in the night sky. Observing this scintillation indicates that the region where the FRB originated must be incredibly small. We have pinpointed the emission site to a size of less than 10,000 kilometres, despite the FRB originating over 200 million light-years away. This extraordinary precision reveals that the FRB must have come from the intensely magnetic environment surrounding a neutron star, one of the most extreme environments in the universe.”
McGill concluded that, “Together, the Mckinven- and Nimmo-led studies make a strong new case that this FRB – and by extension, others – have their origins in a neutron star.”
