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Chinese and Japanese astronomers have detected the most powerful gamma rays recorded so far from an explosion that occurred 1,000 years ago.
Astronomers have celebrated the discovery of the highest energy cosmic gamma rays ever observed in space, dwarfing any others detected so far. The rays seen by the Tibet ASgamma telescope ranged from 100 teraelectron volts (TeV) to about 450 TeV. By comparison, the highest energy ever observed for a gamma-ray photon prior to this was 75 TeV, by the HEGRA Cherenkov telescope.
The researchers behind the joint Chinese and Japanese project believe that the powerful gamma rays were produced by the interaction between very-high-energy electrons and the cosmic microwave background radiation produced by the Big Bang.
They were pinpointed to a region of space known as the Crab Nebula, a famous supernova remnant in the constellation Taurus located approximately 6,500 light years away. It formed in 1054AD by a supernova explosion and was so powerful that it was observed by Chinese and Japanese scholars at the time.
In attempts to determine what could have produced such record-breaking rays, the researchers – whose work has been published to Physical Review Letters – believe it to be the most powerful, natural particle accelerator discovered in our galaxy to date.
The astronomers’ work likely opens a new avenue for the exploration of the extreme universe. The detection of gamma rays above 100 TeV is a key to understanding the origin of very-high-energy cosmic rays, which has been a mystery since their discovery in 1912.
With further observations using this powerful telescope, they are hopeful of finding the origin of cosmic rays in our galaxy, namely PeVatrons (PeV), which accelerate cosmic rays up to PeV energies.
“This is the very first [detection], but a great step forward,” said Prof Huang Jing, co-spokesperson for the Tibet ASgamma experiment.
“It proves that our techniques worked well and gamma rays with energies up to a few hundred TeV really exist. Our goal is to identify a lot of PeVatrons, which have not yet been discovered and are supposed to produce the highest-energy cosmic rays in our galaxy.”
