Year: 2026
Type: article
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.
Source: The Astrophysical Journal
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
OpenAlex ID: W7118892393