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Main Authors: Qiao, Bing-Qiang, Yao, Yu-Hua, Liu, Wei, Yuan, Qiang, Bi, Xiao-Jun, Hu, Hong-Bo, Guo, Yi-Qing
Format: Preprint
Published: 2021
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Online Access:https://arxiv.org/abs/2102.13498
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author Qiao, Bing-Qiang
Yao, Yu-Hua
Liu, Wei
Yuan, Qiang
Bi, Xiao-Jun
Hu, Hong-Bo
Guo, Yi-Qing
author_facet Qiao, Bing-Qiang
Yao, Yu-Hua
Liu, Wei
Yuan, Qiang
Bi, Xiao-Jun
Hu, Hong-Bo
Guo, Yi-Qing
contents The spatial-dependent-propagation (SDP) model with a nearby source works well to reproduce the coevolving features of both cosmic-ray (CR)-nuclei spectra and anisotropy. However, it is well known that the Sun is actually deviating from the galactic disk. This will lead to a dominating anisotropy in the direction perpendicular to the galactic disk, which is discrepant with current observations. Thus, it is necessary to further investigate the effect of the solar offset on anisotropy. In this work, to the best of our knowledge, this is the first time that the combined studies of the solar offset, nuclei spectra, and anisotropy have been performed based on the SDP model. As a result, to reproduce CR spectra and anisotropy, the thickness of the inner halo $ (Z_{IH})$ needs to increase linearly with the displacement of the Sun. We also know that the PeV anisotropy could be used to estimate the value of the diffusion coefficient, thus breaking the degeneracy between the diffusion coefficient and halo thickness. Therefore, it is a good approach to constrain the halo thickness. Moreover, the anisotropy in the PeV energy region, as a new probe, might also shed new light on constraining the solar offset. It is hoped that the anisotropy of the energies from $\rm \sim$TeV to $\rm PeV$ can be finely measured with the LHAASO experiment, leading to a better understanding of the thick halo.
format Preprint
id arxiv_https___arxiv_org_abs_2102_13498
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Constraining the Thickness of the Galactic Halo through Cosmic-Ray Anisotropy Using the Spatial-Dependent-Propagation Model
Qiao, Bing-Qiang
Yao, Yu-Hua
Liu, Wei
Yuan, Qiang
Bi, Xiao-Jun
Hu, Hong-Bo
Guo, Yi-Qing
High Energy Astrophysical Phenomena
The spatial-dependent-propagation (SDP) model with a nearby source works well to reproduce the coevolving features of both cosmic-ray (CR)-nuclei spectra and anisotropy. However, it is well known that the Sun is actually deviating from the galactic disk. This will lead to a dominating anisotropy in the direction perpendicular to the galactic disk, which is discrepant with current observations. Thus, it is necessary to further investigate the effect of the solar offset on anisotropy. In this work, to the best of our knowledge, this is the first time that the combined studies of the solar offset, nuclei spectra, and anisotropy have been performed based on the SDP model. As a result, to reproduce CR spectra and anisotropy, the thickness of the inner halo $ (Z_{IH})$ needs to increase linearly with the displacement of the Sun. We also know that the PeV anisotropy could be used to estimate the value of the diffusion coefficient, thus breaking the degeneracy between the diffusion coefficient and halo thickness. Therefore, it is a good approach to constrain the halo thickness. Moreover, the anisotropy in the PeV energy region, as a new probe, might also shed new light on constraining the solar offset. It is hoped that the anisotropy of the energies from $\rm \sim$TeV to $\rm PeV$ can be finely measured with the LHAASO experiment, leading to a better understanding of the thick halo.
title Constraining the Thickness of the Galactic Halo through Cosmic-Ray Anisotropy Using the Spatial-Dependent-Propagation Model
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2102.13498