Ultrahard spectra of PeV neutrinos from supernovae in compact star clusters

TL;DR

This paper proposes that supernovae in compact star clusters can accelerate protons to PeV energies, producing high-energy neutrinos detectable by IceCube, thus explaining some observed astrophysical neutrino flux.

Contribution

It introduces a novel mechanism for PeV neutrino production involving supernova shocks in star clusters, expanding understanding of cosmic ray acceleration sources.

Findings

Supernova shocks in star clusters can accelerate protons to ~40 PeV.

Accelerated protons produce high-energy neutrinos and gamma-rays.

Neutrino fluxes from such sources may account for IceCube observations.

Abstract

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. Once accelerated, these CRs will diffuse into surrounding dense clouds and produce neutrinos with fluxes sufficient to explain a fraction of the events detected by IceCube Observatory from the inner Galaxy.