Probing the Penrose Process at the Center of the Milky Way

• New research investigates whether the Penrose process, a method of extracting energy directly from a rotating black hole, can be observed at the center of the Milky Way.
• The study suggests that Sgr A* could act as a 'galactic PeVatron' through the magnetic Penrose process (MPP).

The Penrose Process and the Ergosphere

• Proposed by Roger Penrose in 1969, the mechanism describes extracting energy from a rotating black hole, thereby reducing its total mass.
• This occurs within the ergosphere, a region where frame dragging is so extreme that any object is forced to co-rotate with the black hole.
• By dumping matter into the hole while within this region, the remaining system gains energy, while the black hole absorbs negative energy and loses mass.

The Magnetic Penrose Process (MPP)

• The researchers analyzed the decay of neutrons within the ergosphere of Sgr A* rather than hypothetical space debris.
• A neutron decays into a proton, an electron, and a neutrino; the charged products then interact with the black hole's magnetic field.
• The MPP could accelerate protons to the PeV (peta electron volt) range, making them a thousand times more powerful than particles in the Large Hadron Collider.
• These protons would strike nearby gas, producing distinct gamma-ray signatures and high-energy neutrinos.

Observation and Future Prospects

• Current detection technology is insufficient to capture these faint signals from the galactic center.
• Future upgrades to the High-Altitude Water Cherenkov (HAWC) observatory and the next-generation IceCube Neutrino Observatory are expected to provide the necessary sensitivity to confirm the process.