Very-High-Energy Gamma-Ray Signal from Nuclear Photodisintegration as a Probe of Extragalactic Sources of Ultrahigh-Energy Nuclei

摘要

It is crucial to identify the ultrahigh-energy cosmic-ray (UHECR) sources andprobe their unknown properties. Recent results from the Pierre AugerObservatory favor a heavy nuclear composition for the UHECRs. Under therequirement that heavy nuclei survive in these sources, using gamma-ray burstsas an example, we predict a diagnostic gamma-ray signal, unique to nuclei - theemission of de-excitation gamma rays following photodisintegration. These gammarays, boosted from MeV to TeV-PeV energies, may be detectable by gamma-raytelescopes such as VERITAS, HESS, and MAGIC, and especially the next-generationCTA and AGIS. They are a promising messenger to identify and study individualUHE nuclei accelerators.