Heavy nuclei at the end of the cosmic-ray spectrum?

ANCHORDOQUI, L. A.; ROMERO, G. E.; COMBI, J. A.

PHYSICAL REVIEW D - PARTICLE AND FILDS

APS

Año: 1999 vol. 60 p. 1030011 - 1030016

0556-2821

We provide an account of the possible acceleration of iron nuclei up to energies ~300 EeV in the nearby, metally-rich starburst galaxy NGC 253. It is suggested that particles can escape from the nuclear region with energies of ~1015 eV and then could be reaccelerated at the terminal shock of the galactic superwind generated by the starburst, avoiding in this way the photodisintegration expected if the nuclei were accelerated in the central region of high photon density. We have also made estimates of the expected arrival spectrum, which displays a strong dependency with the energy cutoff at the source.