Ultraheavy Cosmic Rays from Magnetars
- 1Columbia University
- 2Institute for Advanced Study
- 3Flatiron Institute
Abstract
Matter ejected from the neutron star crust during a magnetar giant flare will undergo r -process nucleosynthesis during decompression. Ultraheavy ions ( Z ≫ 26) may be accelerated to cosmic-ray energies by the reverse shock as the ejecta decelerates upon interacting with the ambient environment. We investigate the contribution of magnetars to the local ultraheavy cosmic-ray flux using semianalytic Galactic transport calculations, demonstrating that they may be significant contributors throughout Galactic history depending on the giant flare rate and ion acceleration efficiency. Although neutron star mergers inject orders of magnitude more energy into cosmic rays, they rarely occur within the spallation-limited propagation horizon for ultraheavy species, reducing their local contributions. As compared to lighter nuclei, which are dominantly accelerated by supernovae, the SuperTIGER experiment has presented tentative evidence for a distinct contribution to the cosmic-ray abundances near and above the first r -process peak ( Z ≈ 35–56). We argue that current abundance data may be consistent with either a magnetar giant flare or neutron star merger origin for these species. Measurements with single-element resolution through the third r -process peak, expected from the upcoming TIGERISS experiment, are required to discriminate between these sources for the heaviest cosmic rays.
Related
- Microquasars as the major contributors to Galactic cosmic rays around the knee
- Dark-matter relay for ultra-high-energy cosmic rays
- Lightest and heaviest nuclei as keys to the origin of ultrahigh energy cosmic rays
- Observation of the Moon and Sun shadows with cosmic rays at an average energy of 7×1017eV
- Transient Large-Scale Anisotropy in TeV Cosmic Rays due to an Interplanetary Coronal Mass Ejection
BibTeX
@article{patel2026ultraheavy,
title = {{Ultraheavy Cosmic Rays from Magnetars}},
author = {Anirudh Patel and Rebecca Diesing and Brian D. Metzger},
journal = {The Astrophysical Journal},
year = {2026},
month = oct,
doi = {10.3847/1538-4357/ae9c27},
url = {https://iopscience.iop.org/article/10.3847/1538-4357/ae9c27},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Ultraheavy Cosmic Rays from Magnetars
AU - Anirudh Patel
AU - Rebecca Diesing
AU - Brian D. Metzger
PY - 2026
DA - 2026/10/05
JO - The Astrophysical Journal
DO - 10.3847/1538-4357/ae9c27
UR - https://iopscience.iop.org/article/10.3847/1538-4357/ae9c27
AB - Matter ejected from the neutron star crust during a magnetar giant flare will undergo r -process nucleosynthesis during decompression. Ultraheavy ions ( Z ≫ 26) may be accelerated to cosmic-ray energies by the reverse shock as the ejecta decelerates upon interacting with the ambient environment. We investigate the contribution of magnetars to the local ultraheavy cosmic-ray flux using semianalytic Galactic transport calculations, demonstrating that they may be significant contributors throughout Galactic history depending on the giant flare rate and ion acceleration efficiency. Although neutron star mergers inject orders of magnitude more energy into cosmic rays, they rarely occur within the spallation-limited propagation horizon for ultraheavy species, reducing their local contributions. As compared to lighter nuclei, which are dominantly accelerated by supernovae, the SuperTIGER experiment has presented tentative evidence for a distinct contribution to the cosmic-ray abundances near and above the first r -process peak ( Z ≈ 35–56). We argue that current abundance data may be consistent with either a magnetar giant flare or neutron star merger origin for these species. Measurements with single-element resolution through the third r -process peak, expected from the upcoming TIGERISS experiment, are required to discriminate between these sources for the heaviest cosmic rays.
SN - 0004-637X
SN - 1538-4357
ER -