# High-energy cosmic rays from compact galactic star clusters: particle fluxes and anisotropy

## TL;DR

This paper explores how compact galactic star clusters could produce high-energy cosmic rays and influence their observed fluxes and anisotropy, suggesting they may significantly contribute to cosmic rays around 100 PeV without conflicting with anisotropy observations.

## Contribution

It introduces a model of cosmic-ray production from star clusters and examines their impact on flux and anisotropy, extending understanding of cosmic-ray origins at ultra-high energies.

## Key findings

- Star clusters can produce cosmic rays above 10^{17} eV.
- Galactic star clusters may account for a substantial fraction of 100 PeV cosmic rays.
- The model aligns with observed cosmic-ray anisotropy levels.

## Abstract

It has been shown that supernova blast waves interacting with winds from massive stars in compact star clusters may be capable of producing cosmic-ray (CR) protons to above $10^{17}$ eV. We give a brief description of the colliding-shock-flows mechanism and look at generalizations of the diffusion of ~ 100 PeV CRs in the turbulent galactic magnetic field present in the galactic disk. We calculate the temporal evolution of the CR anisotropy from a possible distribution of young compact massive star clusters assuming the sources are intermittent on time scales of a few million years, i.e., comparable to their residence time in the Milky Way. Within the confines of our model, we determine the galactic/extra-galactic fraction of high-energy CRs resulting in anisotropies consistent with observed values. We find that galactic star clusters may contribute a substantial fraction of ~ 100 PeV CRs without producing anisotropies above observed limits.