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arXiv · 1511.01333

A signature of EeV protons of Galactic origin

P. G. Tinyakov·F. R. Urban·D. Ivanov·G. B. Thomson·A. H. Tirone
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Abstract

We investigate signatures that would be produced in the spectrum and sky distribution of UHECR by a population of the Galactic sources of high-energy protons in the energy range around 1~EeV, i.e., around the diffusive-to-ballistic transition. In this regime, the CR flux has to be calculated numerically. We employ the approach that consists in backtracking anti-protons from Earth through the Galaxy and integrating the source emissivity along the trajectory. This approach makes evident two generic features of the transition region: sharp increase of the total flux as the energy decreases across the transition region, and its strong anisotropy (appearance of a bright compact spot) all the way until the onset of the diffusive regime. We then discuss and compare several methods to experimentally detect or constrain these features. We find that a few percent admixture of the Galactic protons can in principle be detected by the current UHECR experiments.

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P. G. Tinyakov, F. R. Urban, D. Ivanov, G. B. Thomson, A. H. Tirone. 2016-06-27. A signature of EeV protons of Galactic origin. https://doi.org/10.1093/mnras%2Fstw1163

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