Constraining the sources of ultra-high-energy cosmic rays across and above the ankle with the spectrum and composition data measured at the Pierre Auger Observatory
Constraining the sources of ultra-high-energy cosmic rays across and above the ankle with the spectrum and composition data measured at the Pierre Auger Observatory
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DOI：
10.1088/1475-7516/2023/05/024
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发表时间：
2022-11
影响因子：
6.4
通讯作者：
T. P. A. A. Halim-T.-P.-A.-A.-Halim-2190109076;P. Abreu;M. Aglietta;I. Allekotte;K. A. Cheminant;A. Almela;J. Alvarez-Muñiz
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作者：
T. P. A. A. Halim-T.-P.-A.-A.-Halim-2190109076;P. Abreu;M. Aglietta;I. Allekotte;K. A. Cheminant;A. Almela;J. Alvarez-Muñiz
在这项工作中，我们提出了解释的能量谱和质量组成的数据所测量的皮埃尔俄歇合作超过6 × 1017 eV。我们使用一个天体物理模型，两个河外源人口的宇宙射线通量在5 × 1018 eV左右（所谓的“脚踝”功能）作为这两个组件之间的过渡模型的硬化。我们发现我们的数据被很好地再现，如果源以上的脚踝发出一个混合的组成与硬光谱和低刚度截止。脚踝以下的部分需要有一个非常软的光谱和质子和中等质量核的混合。这个中等质量的成分的起源没有很好的约束，它可能来自银河系或河外来源。为了评估我们约束天体物理模型的能力，我们讨论了主要实验系统的不确定性和影响空气簇射发展以及注入的超高能宇宙线（UHECRs）的传播和红移分布的量的假设对拟合结果的影响。
In this work we present the interpretation of the energy spectrum and mass composition data as measured by the Pierre Auger Collaboration above 6 × 1017 eV. We use an astrophysical model with two extragalactic source populations to model the hardening of the cosmic-ray flux at around 5 × 1018 eV (the so-called “ankle” feature) as a transition between these two components. We find our data to be well reproduced if sources above the ankle emit a mixed composition with a hard spectrum and a low rigidity cutoff. The component below the ankle is required to have a very soft spectrum and a mix of protons and intermediate-mass nuclei. The origin of this intermediate-mass component is not well constrained and it could originate from either Galactic or extragalactic sources. To the aim of evaluating our capability to constrain astrophysical models, we discuss the impact on the fit results of the main experimental systematic uncertainties and of the assumptions about quantities affecting the air shower development as well as the propagation and redshift distribution of injected ultra-high-energy cosmic rays (UHECRs).