The shortest gamma-ray burst turned out to be a "misfire" of a supernova

The shortest gamma-ray burst turned out to be a "misfire" of a supernova
The shortest gamma-ray burst turned out to be a "misfire" of a supernova

Astronomers have studied the short gamma-ray burst 200826A and linked it to a supernova that exploded billions of light years away.


Gamma-ray bursts are one of the most powerful processes in the universe. In a matter of moments of the outburst, as much energy is released as the sun does not emit during its entire existence. The sources of gamma-ray bursts are located in distant galaxies, and their nature has not been finally established, although it is known that they arise as a result of the collapse of matter, in which part of it is ejected by narrow jets at near-light speed, emitting in the hard wavelength range. If the stream is directed in our direction, it can be seen even after ten billion light years.

Long gamma-ray bursts (longer than a couple of seconds) are associated with supernova explosions and the vicinity of black holes, and short gamma-ray bursts are attributed to mergers of neutron stars and black holes. However, the GRB 200826A gamma-ray burst does not fit well into such a scheme: despite the record shortness of 0.65 seconds, it is associated with a supernova. This is reported in a new article published in the journal Nature Astronomy.

GRB 200826A was recorded on August 26, 2020 by the Fermi space gamma-ray observatory. “The explosion emitted 14 million times more energy than the entire Milky Way in the same time span, making it one of the most powerful short gamma-ray bursts on record,” says Tomas Ahumada, one of the authors of the paper. "However, we believe that it was the result of a misfire and might not have happened at all."

Scientists have collected data on GRB 200826A, which have obtained other available instruments, including the American Wind, the European INTEGRAL, and even the sensors of the Mars Odyssey probe. This made it possible to more accurately localize the source of the gamma-ray burst - a narrow region in the constellation Andromeda. The authors of the work examined this area in images taken by the telescopes of the Gemini Observatory 28, 45 and 80 days later, and discovered a rapidly fading supernova explosion at a distance of about 6, 6 billion light years.

Apparently, it was she who created the unusually short gamma-ray burst. Scientists suggest that the jets ejected by the dying star were too weak. The particles could not overcome its outer shells, slowed down and fell into the bowels of the forming black hole. Instead of a full-fledged gamma-ray burst, we got a "misfire" - an abnormally short burst GRB 200826A.

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