First detection of an intense radio burst from a Galactic magnetar
On 28 April 2020, a team of approximately 50 students, postdocs and
professors from the Canadian Hydrogen Intensity Mapping Experiment (CHIME)
Fast Radio Burst Collaboration detected an unusually intense radio burst
emanating from a nearby magnetar located in the Milky Way. In a study
published today in Nature, they show that the intensity of the radio burst
was three thousand times greater than that of any magnetar measured thus
far, lending weight to the theory that magnetars are at the origin of at
least some FRBs.
"We calculated that such an intense burst coming from another galaxy would
be indistinguishable from some fast radio bursts, so this really gives
weight to the theory suggesting that magnetars could be behind at least some
FRBs," said Pragya Chawla, one of the co-authors on the study and a senior
PhD student in the Physics Department at McGill.
Competing theories about the origins of FRBs
FRBs were first discovered over a decade ago. Originally thought to be
singular events, astronomers have since discovered that some of these
high-intensity blasts of radio emissions -- more intense than the energy
generated by the Sun over millions to billions of years -- in fact repeat.
One theory hypothesized FRBs to be extragalactic magnetars -- young
extremely magnetic neutron stars that occasionally flare to release enormous
amounts of energy.
"So far, all of the FRBs that telescopes like CHIME have picked up were in
other galaxies, which makes them quite hard to study in great detail," said
Ziggy Pleunis, a senior PhD student in McGill's Physics department and one
of the co-authors of the new study. "Moreover, the magnetar theory was not
supported by observations of magnetars in our own galaxy as they were found
to be far less intense than the energy released by extragalactic FRBs until
now."
Magnetar origin for all FRBs remains to be confirmed
"However, given the large gaps in energetics and activity 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 FRB observations," added Dr. Paul Scholz from the Dunlap Institute of
Astronomy and Astrophysics at the University of Toronto.
Smoking-gun proof of a magnetar origin for some FRBs would come from the
simultaneous detection of an extragalactic radio burst and an X-ray burst.
However, this will likely only be possible for nearby FRBs. Fortunately,
CHIME/FRB is discovering these in good numbers.
Reference:
CHIME/FRB Collaboration. A bright millisecond-duration radio burst from a
Galactic magnetar,. Nature, 2020 DOI:
10.1038/s41586-020-2863-y
Tags:
Space & Astrophysics