Ultrahigh-energy cosmic rays from tidally-ignited white dwarfs

Understand

Ultra-high-energy cosmic rays (UHECRs) can be accelerated by tidal disruption events of stars by black holes.

• We suggest a novel mechanism for UHECR acceleration wherein white dwarfs (WDs) are tidally compressed by intermediate-mass black holes (IMBHs), leading to their ignition and subsequent explosion as a supernova.
• Cosmic rays accelerated by the supernova may receive an energy boost when crossing the accretion-powered jet.
• The rate of encounters between WDs and IMBHs can be relatively high, as the number of IMBHs may be substantially augmented once account is taken of their likely presence in dwarf galaxies.