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Scientists using data from NASA's Fermi mission

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have pinpointed a “PeVatron,”

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an elusive source of cosmic ray particles here.

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Cosmic rays strike our atmosphere every day.

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They're mostly protons, and come in a broad range of energies.

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The highest-energy particles made within our own galaxy

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exceed 1,000 trillion electron volts (PeV).

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That's 10 times the energy reached by the world’s most powerful particle collider.

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Locating PeV sources, or PeVatrons, isn’t easy.

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music

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Like all cosmic rays, their paths to Earth become scrambled by magnetic fields.

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But when these particles strike other matter,

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they produce gamma rays,

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high-energy light that travels straight to us.

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This stellar wreckage

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was already a prime PeVatron suspect.

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Supernova remnant. PeVatron.

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Gas cloud.

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And with 12 years of Fermi data, the connection's even clearer.

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About 10,000 years ago,

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a powerful supernova exploded at this spot.

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What remains now is a bright gamma-ray pulsar

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and a blast wave that's still expanding into space.

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Protons ensnared in this blast wave keep gaining energy

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until they eventually break out.

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They eventually hit the gas cloud,

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producing the tell-tale gamma rays Fermi sees.

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One PeVatron down.  How many more are out there?

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Multiwavelength image byJayanne English, University of Manitoba,NASA/Fermi/Fang et al. 2022,and Canadian Galactic Plane Survey/DRAO/FCRAO