The Influence of Sun's and Moon's Shadows on Cosmic-Ray Anisotropy

Fuente: arXiv
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Main Authors: Ye, Xuan'ang, Zhang, Yi, He, Jiayin, Zhao, Shiping
Format: Preprint
Published: 2025
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author Ye, Xuan'ang
Zhang, Yi
He, Jiayin
Zhao, Shiping
author_facet Ye, Xuan'ang
Zhang, Yi
He, Jiayin
Zhao, Shiping
contents Large-scale anisotropy, with amplitudes reaching approximately 0.1% at TeV energies, has been observed by multiple cosmic-ray experiments. The obstruction of cosmic rays by the Sun and Moon creates shadow effects, potentially impacting the observed cosmic ray anisotropy. To evaluate these effects, this study calculates the contributions of the Sun's and Moon's shadows to the overall cosmic-ray anisotropy in both local solar and sidereal time. The analysis reveals that in local sidereal time, the total 1D projection amplitude of the anisotropy is around 0.003%, which is significantly smaller than the observed cosmic-ray anisotropy. This indicates that the influence of the Sun's and Moon's shadows on cosmic-ray anisotropy analysis in local sidereal time is negligible. In contrast, in local solar time, the shadow-induced deficit appears in a very small time bin, with a magnitude comparable to that of the cosmic-ray solar anisotropy. This deficit could serve as a benchmark for validating anisotropy measurements in future facilities.
format Preprint
id arxiv_https___arxiv_org_abs_2502_09108
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Influence of Sun's and Moon's Shadows on Cosmic-Ray Anisotropy
Ye, Xuan'ang
Zhang, Yi
He, Jiayin
Zhao, Shiping
High Energy Astrophysical Phenomena
Large-scale anisotropy, with amplitudes reaching approximately 0.1% at TeV energies, has been observed by multiple cosmic-ray experiments. The obstruction of cosmic rays by the Sun and Moon creates shadow effects, potentially impacting the observed cosmic ray anisotropy. To evaluate these effects, this study calculates the contributions of the Sun's and Moon's shadows to the overall cosmic-ray anisotropy in both local solar and sidereal time. The analysis reveals that in local sidereal time, the total 1D projection amplitude of the anisotropy is around 0.003%, which is significantly smaller than the observed cosmic-ray anisotropy. This indicates that the influence of the Sun's and Moon's shadows on cosmic-ray anisotropy analysis in local sidereal time is negligible. In contrast, in local solar time, the shadow-induced deficit appears in a very small time bin, with a magnitude comparable to that of the cosmic-ray solar anisotropy. This deficit could serve as a benchmark for validating anisotropy measurements in future facilities.
title The Influence of Sun's and Moon's Shadows on Cosmic-Ray Anisotropy
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2502.09108