The large-scale anisotropy and flux (de-)magnification of ultra-high-energy cosmic rays in the Galactic magnetic field

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Hauptverfasser: Bister, Teresa, Farrar, Glennys R., Unger, Michael
Format: Preprint
Veröffentlicht: 2024
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author Bister, Teresa
Farrar, Glennys R.
Unger, Michael
author_facet Bister, Teresa
Farrar, Glennys R.
Unger, Michael
contents We calculate the arrival direction distribution of ultra-high-energy cosmic rays (UHECRs) with a new suite of models of the Galactic magnetic field (GMF), assuming sources follow the large-scale structure of the Universe. Compared to previous GMF models, the amplitude of the dipole component of the UHECR arrival flux is significantly reduced. We find that the reduction is due to the accidentally coinciding position of the peak of the extragalactic UHECR flux and the boundary of strong flux demagnification due to the GMF toward the central region of the Galaxy. This serendipitous sensitivity of UHECR anisotropies to the GMF model will be a powerful probe of the source distribution as well as Galactic and extragalactic magnetic fields. Demagnification by the GMF also impacts visibility of some popular source candidates.
format Preprint
id arxiv_https___arxiv_org_abs_2408_00614
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The large-scale anisotropy and flux (de-)magnification of ultra-high-energy cosmic rays in the Galactic magnetic field
Bister, Teresa
Farrar, Glennys R.
Unger, Michael
High Energy Astrophysical Phenomena
We calculate the arrival direction distribution of ultra-high-energy cosmic rays (UHECRs) with a new suite of models of the Galactic magnetic field (GMF), assuming sources follow the large-scale structure of the Universe. Compared to previous GMF models, the amplitude of the dipole component of the UHECR arrival flux is significantly reduced. We find that the reduction is due to the accidentally coinciding position of the peak of the extragalactic UHECR flux and the boundary of strong flux demagnification due to the GMF toward the central region of the Galaxy. This serendipitous sensitivity of UHECR anisotropies to the GMF model will be a powerful probe of the source distribution as well as Galactic and extragalactic magnetic fields. Demagnification by the GMF also impacts visibility of some popular source candidates.
title The large-scale anisotropy and flux (de-)magnification of ultra-high-energy cosmic rays in the Galactic magnetic field
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2408.00614