Hundreds of gamma ray signals were detected with ultra-high energies, with the most powerful signals crossing the Peta-electronvolt (PeV) threshold – much higher than thought possible in our galaxy.

Gamma rays are the most energetic type of electromagnetic radiation, released during extreme events like supernovae, matter-antimatter annihilation, and the activity of objects like pulsars. They're often detected with energies in the Giga-electrovolt (GeV) range, but they've been known to occasionally top the Tera-electronvolt (TeV) mark, which is 1,000 GeV.

In 2019, the Crab Nebula stole the crown for most energetic gamma rays ever detected, at 100 TeV. That was considered pretty close to the upper limit for how energetic sources could ever get in our Milky Way – but now that ceiling has been utterly shattered.