Ever since they were discovered more than a decade ago, fast radio bursts, or FRBs—powerful, millisecond-duration radio waves that come from deep space—have kept astrophysicists guessing about their origins. Now, papers published in the Nature journal this month reveal more about the physical mechanisms of FRBs, and a possible source of origin.
In one study, researchers from the University of Nevada, Las Vegas and other international collaborators used the Five-hundred-meter Aperture Spherical Telescope (or FAST) in Guizhou, China, for observations that helped them come up with two theories on the mechanism of FRBs. One theory sees them as similar to gamma-ray bursts, the most powerful explosions in the universe. The other theory, which looks likelier, is that they are more like radio pulsars, or spinning neutron stars that emit bright radio pulses.
Four other papers on FRBs have helped scientists understand more about their origins. Researchers working with the Canadian Hydrogen Intensity Mapping Experiment (CHIME) and the Survey for Transient Astronomical Radio Emission 2 (STARE2)—two radio telescope arrays—found conclusive evidence of radio bursts emerging from a magnetar in our Milky Way galaxy.
“CHIME and STARE2 did excellent work in detecting this bright burst across large radio frequencies and confirming the location of the burst to be a previously known magnetar; SGR 1935+2154. Magnetars are highly magnetized neutron stars that are leftover by-products of massive stars,” says Vishal Gajjar, a Templeton postdoctoral research fellow at the Berkeley SETI research centre at the University of California. Gajjar is also part of the Breakthrough Listen project team, a programme that is working on finding evidence of civilisations beyond Earth.
According to a news release, the first conclusive evidence of the magnetar, located about 30,000 light years from Earth, came on 28 April, when an extremely bright radio burst was detected. “We already know of several dozen magnetars in our galaxy by detecting their output energies in X-rays and gamma rays,” says Gajjar. “This new magnetar is unique as no other radio-emitting transient source has ever been seen to show such bright emission. The radio burst was so powerful that if we placed this magnetar in another galaxy, several thousand light years away, we could still detect it very easily,” he adds on email. “In my opinion, this is a significant discovery.”
