Can ultrahigh energy cosmic rays come from gamma-ray bursts? Constraints on galactic sources such as long GRB

We study the propagation of ultra-high-energy cosmic rays (UHECR) in the Galaxy, concentrating on the energy range below the ankle. A Monte-Carlo method based on analytical solutions to the time-dependent diffusion problem is used to account for intermittency. Assuming a source population that scales as Galactic baryon density, we derive constraints arising from intermittency and the requiring to satisfy observational limits on the composition and anisotropy. It is shown that the composition and anisotropy at 1e18 eV are difficult to reproduce and require that either the particle mean free path is unusually small of the composition is heavier than suggested by recent Auger data. We therefore consider it highly desirable that steps be taken to reduce the systematic uncertainty in the experimental derivation of the UHECR composition around 1e18 eV.