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Astronomers using the Canadian Hydrogen Intensity Mapping Experiment (CHIME) and Five-100-meter Aperture Spherical radio Telescope (FAST) telescopes have detected an extremely intense radio burst from SGR 1935 + 2154, a magnetar located at 4,400 parsecs (14,351 years light) away in the constellation of Vulpecula.
An artistic impression of the exploding magnetar SGR 1935 + 2154, showing the complex structure of the magnetic field and the emission of rays. Image credit: McGill University Graphic Design Team.
Fast 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 detection of the Magellanic Clouds.
FRBs have a duration of milliseconds and show the characteristic scattering scan 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 speculated that FRBs were extragalactic magnetars, highly magnetized young neutron stars that occasionally produce huge bursts and flares of X-rays and gamma rays.
“Until now, all the FRBs detected by telescopes like CHIME were in other galaxies, which makes them quite difficult to study in great detail,” said co-author Ziggy Pleunis, Ph.D. student in McGill University’s Department of Physics.
‘Furthermore, the magnetar theory was not supported by observations of the magnetars in our galaxy as they were found to be far less intense than the energy released by the extragalactic FRBs until now.’
Using the CHIME radio telescope, Pleunis and colleagues detected the millisecond-duration bright radio burst, dubbed FRB 200428, by the magnetar SGR 1935 + 2154.
The intensity of the event was three orders of magnitude higher than the burst energy of any radium-emitting magnetar detected so far, giving weight to the theory that magnetars are at the origin of at least some FRBs.
“We calculated that such an intense explosion from another galaxy would be indistinguishable from some FRBs, so this really gives weight to the theory that suggests that magnetars may be behind at least some FRBs,” said co-author Pragya Chawla, Ph. .D. student in the Physics Department of McGill University.
“Given the large energy and activity gaps between the brightest and most active FRB sources and what is observed for magnetars, perhaps younger, more energetic and active magnetars are needed to explain all the FRB observations,” said the co-author. Dr. a researcher at the Dunlap Institute of Astronomy and Astrophysics at the University of Toronto.
In a separate study, University of Nevada astronomer Bing Zhang and colleagues used the FAST radio telescope to conduct multiband observations of SGR J1935 + 2154.
“We now know that the most magnetized objects in the universe, so-called magnetars, can produce at least some or perhaps all of the FRBs in the universe,” said Dr. Zhang.
The findings 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 bright radio burst lasting milliseconds 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 an outbreak of a galactic magnetar. Nature 587, 63-65; doi: 10.1038 / s41586-020-2839-y
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