Friday, December 30, 2011

1112.6388 (Daniele Fargion)

Apart Cen A are UHECR mostly radioactive and heavy galactic nuclei?    [PDF]

Daniele Fargion
Recent UHECR mass compositions did show a negligible nucleon composition and an UHECR nuclei (light or heavy) signatures. The absence of UHECR events toward Virgo cluster, the unique spread clustering of events around Cen-A, our nearest AGN, suggested a He-like nuclei as the main extragalactic UHECR component from Cen A, coexisting with Auger and HIRES composition. Because the light nuclei fragility such He UHECR cannot arrive from Virgo (being too far). Multiplet at tens EeV along Cen A confirm this interpretation as foreseen fragments (D;He3; p). However remaining majority of UHECR clustering are partially correlated with Al26 galactic radioactive MeV map; also a few TeV gamma anisotropy maps seem to correlate ; rare UHECR triplet are overlapping on Vela TeV anisotropy and other nearest galactic gamma sources (as partially Crab and Galactic Center core). Therefore UHECR might be also (or mostly) heavy radioactive galactic nuclei as Ni56, Ni57 and Co57 bent from the sources whose radioactivity and decay in flight is boosted (Lorentz factor near a billion) leading to and tracing TeV correlated sky anisotropy. The UHECR spectra cut maybe not an extragalactic GZK feature but the imprint of a galactic confinement.
View original: http://arxiv.org/abs/1112.6388

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