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Contribution Oral
Ultrahigh energy cosmic rays as heavy nuclei from cluster accretion shocks
Speakers
- Dr. Susumu INOUE
Primary authors
- Dr. Susumu INOUE (National Astronomical Observatory of Japan)
Co-authors
- Dr. Günter SIGL (APC and IAP, Paris, France)
- Dr. Francesco MINIATI (ETH Zürich, Switzerland)
- Dr. Eric ARMENGAUD (DSM/DAPNIA, France)
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Abstract content
Large-scale accretion shocks around massive clusters of galaxies, generically expected in hierarchical scenarios of cosmological structure formation, are shown to be plausible sources of the observed ultrahigh energy cosmic rays (UHECRs) by accelerating a mixture of heavy nuclei including the iron group elements. Current observations can be explained if the source composition at injection for the heavier nuclei is somewhat enhanced from simple expectations for the accreting gas. The proposed picture should be clearly testable by current and upcoming facilities in the near future through characteristic features in the UHECR spectrum, composition and anisotropy, in particular the rapid increase of the average mass composition with energy from $10^{19}$ to $10^{20}$ eV. The associated X-ray and gamma-ray signatures are also briefly discussed.
Reference
Proceedings of the 30th International Cosmic Ray Conference; Rogelio Caballero, Juan Carlos D'Olivo, Gustavo Medina-Tanco, Lukas Nellen, Federico A. Sánchez, José F. Valdés-Galicia (eds.); Universidad Nacional Autónoma de México, Mexico City, Mexico, 2008; Vol. 4 (HE part 1), pages 555-558