Ultrahard spectra of PeV neutrinos from supernovae in compact star clusters

Understand

Starburst regions with multiple powerful winds of young massive stars and supernova remnants are favorable sites for high-energy cosmic ray acceleration.

• A supernova shock colliding with a fast wind from a compact cluster of young stars allows the acceleration of protons to energies well above the standard limits of diffusive shock acceleration in an isolated SN.
• The proton spectrum in such a wind-supernova PeV accelerator is hard with a large flux in the high-energy-end of the spectrum producing copious gamma-rays and neutrinos in inelastic nuclear collisions.
• We argue that SN shocks in the Westerlund 1 cluster in the Milky Way may accelerate protons to about 40 PeV.