Venerdì 05 Maggio 2023
Scientists record brightest gamma-ray burst ever
The gamma-ray burst (gamma ray flash) captured on October 9, 2022, was the brightest ever seen, according to observations presented at the American Astronomical Society's Division of High Energy Astrophysics conference in Hawaii and published in The Astrophysical Journal Letters and Astronomy & Astrophysics. Italy took part in the research with the National Institute for Astrophysics (INAF), National Institute for Nuclear Physics (INFN) and Italian Space Agency (ASI).
A gamma-ray burst is an extremely rare event, occurring once every 10,000 years as a result of the collapse of the core of a massive star and the subsequent birth of a black hole, which emits jets of very high-energy particles in opposite directions as it engulfs surrounding matter.
The event of October 9, 2022, was so bright that its residual radiation, the so-called 'afterglow’, is still visible and will remain so for a long time. The explosion was 70 times brighter than any other seen in the 55 years since the first satellites to study gamma rays were put into orbit.
The source of the explosion, called GRB 221009A, was identified in a galaxy about 2 billion light-years away. Researchers also expected to observe a supernova a few weeks later, but it was not detected even by the James Webb Space Telescope of NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA). One hypothesis is that the star was so big that a black hole formed immediately after the initial explosion, swallowing all surrounding material.
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