Fermi Gamma-ray Space Telescope discovers the shortest GRB ever seen

Shane McGlaun - Jul 27, 2021, 6:06am CDT
Fermi Gamma-ray Space Telescope discovers the shortest GRB ever seen

NASA has announced that on August 26 of last year, the Fermi Gamma-ray Space Telescope detected a high-energy pulse of radiation that has been moving towards the Earth for nearly half the age of the universe. The pulse detected was extremely short-lasting only about a second, but it set records during its brief existence. The high-energy pulse of radiation was the shortest gamma-ray burst (GRB) ever discovered.

A GRB is caused by the death of a massive star, and they are the most powerful events in the universe. They are so powerful that they can be detected across billions of light-years and classified as long or short based on whether the event lasts for more or less than two seconds. Long bursts are observed during the death of massive stars, while short bursts are linked to a different scenario. Researchers say they already knew some GRBs from massive stars could register as short GRBs, but they believed that was due to instrument limitations.

However, the burst in question, called GRB 200826A, was special because while it was a definite short-duration GRB, it did have other properties pointing to its origin from a collapsing star. Scientists on the study say that now they know dying stars can produce short bursts too. GRB 200826A has been the subject of two research papers. The first explores the gamma-ray data, while the second describes the GRB’s fading multi-wavelength afterglow and the emerging light of the supernova explosion that followed.

Researchers believe the event was essentially “a fizzle” that was close to not happening at all. However, despite its short duration, the burst emitted 14 million times the energy released by the entire Milky Way galaxy over the same amount of time. That means it was one of the most energetic short-duration GRBs ever recorded. Its blast of energy lasted only 0.65 second, but by the time it traveled across the expanding universe and reached Earth, it had stretched to about one second long.


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