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Astronomers using the CHIME (Canadian Hydrogen Intensity Mapping Experiment) and FAST (Five-hundred-meter Aperture Spherical Radio Telescope) telescopes have detected an extremely intense radio burst emanating from SGR 1935 + 2154, a magnetar located at 4400 parsecs (14351 years- light) far away in the constellation Vulpecula.
Artist’s impression of the exploding SGR 1935 + 2154 magnetar, showing a complex magnetic field structure and beam emission. Image Credit: McGill University Graphic Design Team.
Rapid Radio Bursts (FRBs) are mysterious and rarely detected bursts of radio waves from space.
The first FRB was discovered in 2007, although it was actually observed about six years earlier, in archival data from a pulsar Magellanic cloud survey.
FRBs have durations of milliseconds and exhibit the characteristic scatter sweep of radio pulsars.
These events emit as much energy in a millisecond as the Sun emits in 10,000 years, but the physical phenomenon that causes them is unknown.
One theory hypothesized that FRBs were extragalactic magnetars – young, highly magnetized neutron stars that sometimes produce huge bursts and flares of X and gamma rays.
“Until now, all of the FRBs picked up by telescopes like CHIME have been in other galaxies, which makes them quite difficult to study in detail,” said co-author Ziggy Pleunis, a Ph.D. student. in the Department of Physics at McGill University.
“Additionally, the magnetar theory was not supported by observations of magnetars in our own galaxy as they have been shown to be much less intense than the energy released by extragalactic FRBs so far.”
Using the CHIME radio telescope, Pleunis and his colleagues detected the millisecond radio-light burst, dubbed FRB 200428, from the magnetar SGR 1935 + 2154.
The intensity of the event was three orders of magnitude greater than the burst energy of any radio-emitting magnetar detected so far, giving weight to the theory that magnetars are the source of at least some FRB.
“We calculated that such an intense explosion from another galaxy would be indistinguishable from some FRBs, which really lends weight to the theory suggesting that magnetars could be behind at least some FRBs,” the co said. -author Pragya Chawla, a Ph.D. student in the Department of Physics at McGill University.
“Given the large differences in energy and activity between the brightest and most active sources of FRB and what is observed for magnetars, perhaps younger, more energetic and active magnetars are needed. to explain all of the FRB observations, ”said co-author Dr. Paul Scholz, a researcher at the Dunlap Institute of Astronomy and Astrophysics at the University of Toronto.
In another study, University of Nevada astronomer Bing Zhang and his colleagues used the FAST radio telescope to perform multiband observations of the RMS J1935 + 2154.
“We now know that the most magnetized objects in the Universe, the so-called magnetars, can produce at least some or perhaps all of the FRB in the Universe,” said Dr Zhang.
The results were published in two articles in the November 5, 2020 issue of the journal Nature.
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B. Andersen et al. 2020. A brilliant radio burst lasting one millisecond from a galactic magnetar. Nature 587, 54-58; doi: 10.1038 / s41586-020-2863-y
L. Lin et al. 2020. No pulsed radio emission during a burst phase of a galactic magnetar. Nature 587, 63-65; doi: 10.1038 / s41586-020-2839-y
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