They are called “fast radio bursts,” or FRBs, to «fast
radio burst»: hyper intense flashes of radio light, which last between a fraction of a millisecond and a few seconds. Although they were first discovered in 2007, their origin is still unknown. However, astronomers speculate that they are caused by the magnetic fields of a magnetar, a highly magnetic neutron star. Most known FRBs come from outside our galaxy and some repeat themselves, allowing them to be studied in more depth.
In February 2024, the Canadian radio telescope CHIME observed for the first time a rapid radio burst which was to prove repetitive, and which is now known by the sweet code name FRB 20240209A. Between February and June 2024, it was observed twenty-one times. The Canadian team from McGill University was thus able to locate the source of this FRB, which would be some two billion light years away.
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Originally a dead galaxy
Surprise: while most FRBs occur in the most central region of a galaxy (that's where stars form, so that's where the most neutron stars are found), this one comes from the peripheral region of a galaxy. However, this galaxy is more than eleven billion years old, so it is well past its star formation period: it is what we call a “dead galaxy”.
Until now, FRBs were thought to be caused by young magnetars, but this recent discovery proves that old stars can also create FRBs.
-“The results obtained challenge existing theories that link the origins of fast radio bursts to phenomena in star-forming galaxies. The source could be in a globular cluster, a dense region containing old dead stars in the halo of galaxies.explains Vishwagi Shah, doctoral student in the Department of Physics and the Trottier Space Institute at McGill University.
The galaxy concerned is too distant for us to be able to decide on the origin of these FRBs, but this discovery reveals that these bursts occur in much more diverse and unexpected environments than those observed until now.
“This is proof that auxiliary telescopes will radically transform our understanding of fast radio bursts, rejoices Vishwagi Shah. We are on the verge of solving one of the greatest mysteries in astronomy.”
