A spinning black hole can fling particles to PeV energies.

Scientists want to know if Sagittarius A*, the supermassive black hole at our Milky Way's center, can shoot out ultra-high-energy particles. Researchers investigated this by modeling the magnetic Penrose processmagnetic Penrose processA mechanism where spinning black holes transfer rotational energy to charged particles., which pulls rotational energy out of a spinning black hole. Here is how it works: gas swirling around the black hole produces uncharged particles called neutrons. As these neutrons fall toward the black hole, they enter the ergosphereergosphereA region around a rotating black hole where spacetime is dragged so strongly that nothing can stay still., a region right outside where space itself drags along. Inside this zone, the neutrons decay into charged protons. The intense magnetic fields then launch these protons out into space at massive PeV energy levels. When these speeding protons slam into nearby gas clouds, they produce gamma rays and neutrinos. Future observatories like SWGO can detect these distinctive gamma-ray signals, showing that black holes can actively power cosmic radiation.

Why it matters

This shows how the rotational energy of the Galactic center's black hole could produce detectable gamma-rays and neutrinos. It gives astronomers a new way to study high-energy cosmic particles and black hole physics using multiple types of signals.

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