Rare Transients in Nearby Galaxies Explain Ultra-high-energy Cosmic Rays

Fuente: arXiv
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Main Authors: Bartos, Imre, Kowalski, Marek
Format: Preprint
Published: 2025
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author Bartos, Imre
Kowalski, Marek
author_facet Bartos, Imre
Kowalski, Marek
contents The origin of ultra-high-energy cosmic rays remains one of the central open questions in astroparticle physics. Recent measurements reveal anisotropies in arrival directions, a rigidity-dependent composition dominated by intermediate-mass nuclei, and striking hemispheric differences in the energy spectra. Here we show that \emph{rare transients in nearby galaxies} can naturally account for these features. In our fiducial neutron-star merger model, the cosmic ray flux above $25$~EeV is dominated by ten nearby galaxies within $8\,$Mpc. This accounts for the observed hotspots: seven of the ten brightest galaxies coincide with reported excess regions, a chance probability of $p\sim0.001$. Nearby transients can also explain the spectral excess of TA over Auger and modify the rigidity--aligned succession of isotopes.
format Preprint
id arxiv_https___arxiv_org_abs_2510_06193
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Rare Transients in Nearby Galaxies Explain Ultra-high-energy Cosmic Rays
Bartos, Imre
Kowalski, Marek
High Energy Astrophysical Phenomena
The origin of ultra-high-energy cosmic rays remains one of the central open questions in astroparticle physics. Recent measurements reveal anisotropies in arrival directions, a rigidity-dependent composition dominated by intermediate-mass nuclei, and striking hemispheric differences in the energy spectra. Here we show that \emph{rare transients in nearby galaxies} can naturally account for these features. In our fiducial neutron-star merger model, the cosmic ray flux above $25$~EeV is dominated by ten nearby galaxies within $8\,$Mpc. This accounts for the observed hotspots: seven of the ten brightest galaxies coincide with reported excess regions, a chance probability of $p\sim0.001$. Nearby transients can also explain the spectral excess of TA over Auger and modify the rigidity--aligned succession of isotopes.
title Rare Transients in Nearby Galaxies Explain Ultra-high-energy Cosmic Rays
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2510.06193