The Fermi Telescope from NASA has provided new insights about the brightest gamma-ray burst ever recorded, GRB 221009A. Most gamma-ray bursts (GRBs) only last for a second and stem from the core of a dead giant star, known as a neutron star. However, scientists are unsure what causes these stars to release massive amounts of gamma radiation.
In October 2022, astronomers detected GRB 221009A, which came from a supernova approximately 2.4 billion light-years away. This burst was much more intense than any other GRB detected before it, earning the name BOAT (brightest of all time).
An analysis of data from this event revealed the first emission line observed in half a century of studying GRBs with confidence. Emission lines occur when matter interacts with light and can reveal interactions between subatomic particles such as matter and antimatter annihilation, which generates gamma rays.
The new emission line appeared around 5 minutes after the burst was detected and lasted for about 40 seconds. It peaked at an energy level of 12 million electron volts, far more energetic than visible light.
Astronomers believe that this emission line originated from the annihilation of electrons and their antimatter counterparts, positrons, which would have been moving towards Earth at almost the speed of light (99.9%).
“After studying these cosmic explosions for decades, we’re still not entirely sure how they work,” says Elizabeth Hays, Fermi project scientist at NASA’s Goddard Space Flight Center. “Finding clues like this emission line will help us delve deeper into this extreme environment.”
Source: https://cosmosmagazine.com/space/astronomy/brightest-gamma-ray-burst-new-details/