The Fermilab Space Gamma-ray Telescope has detected an unusual feature in a gamma-ray burst that may be the result of the annihilation of matter and antimatter.
NASA’s Fermilab Space Gamma-ray Telescope has investigated what could be the most powerful explosion since the Big Bang, revealing a never-before-seen feature. This phenomenon is called «Brightest Of All Time» or BOAT (Brightest Of All Time).
The gamma-ray burst (GRB) was detected on October 9, 2022, by the Fermilab and the Neil Gehrels Swift Observatory. Scientists assume that the source of BOAT was a supernova that exploded at a distance of almost 2.4 billion light-years from us.
Gamma-ray bursts occur when massive stars run out of fuel for fusion. Their cores collapse, forming black holes that eject powerful jets of matter traveling almost at the speed of light.
BOAT was so powerful that it saturated most gamma-ray detectors in orbit. Statistics show that an event of this magnitude occurs once every 10,000 years. Despite the huge distance, the flare affected the Earth’s atmosphere.
About five minutes after the BOAT was detected, the Fermi telescope recorded an unusual feature in its spectrum — «a possible» emission line. This feature lasted approximately 40 seconds and reached a peak energy of 12 million electron volts. For comparison, visible light has an energy of almost 2-3 electron volts.
The researchers hypothesized the cause of this phenomenon. Maria Edwige Ravasio from Radboud University explains:
«When I first saw this signal, I got goosebumps. Our analysis shows that this is the first highly reliable emission line seen in 50 years of studying gamma-ray bursts».
Scientists suggest that the spectral feature may be the result of the annihilation of electrons and their antimatter twins — positrons. Typically, such annihilation releases energy of about half a million electron volts. However, in the case of BOAT, the recorded energy reached 12 million electron volts. This is due to the fact that the particle jets were moving almost at the speed of light in the direction of the Earth. As a result, the effect of «blue shift» — wave compression occurred, which led to a significant increase in the radiation energy level.
The team’s research published in the journal Science.
Source: Space, Livescience