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arXiv 2007.01768astro-ph.HE
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宇宙射线中光和介质成分谱差异的近源解释

Nearby source interpretation of differences among light and medium composition spectra in cosmic rays

Qiang Yuan, Bing-Qiang Qiao, Yi-Qing Guo, Yi-Zhong Fan, Xiao-Jun Bi

摘要:

最近AMS-02报告了初级宇宙射线中质量成分(氖、镁、硅)能谱的精确测量结果,揭示了与轻成分(氦、碳、氧)不同的性质。本文提出了一个近源方案,并结合背景源的贡献,来解释宇宙线Ne,Mg,Si的新测量谱,特别是它们与He,C,O谱的差异。它们在高能量下的差异可以自然地由附近源的元素丰度来解释。具体地说,Ne、Mg、Si元素的近源与背景的丰度比比He、C、O元素的丰度比低$\sim1.7$倍。这种差异可能是由于祖星的恒星演化或附近源的加速过程/环境的丰度差异。这一方案可以同时解释CREAM/NUCLEON/DAMPE最近揭示的宇宙线谱的高能谱软化特征以及大尺度各向异性的能量依赖行为。据预测,Ne,Mg,Si组的PeV能量以下的偶极各向异性振幅小于He,C,O组,这可以用未来的测量进行测试。

英文摘要:

Recently the AMS-02 reported the precise measurements of the energy spectra of medium-mass compositions (Neon, Magnesium, Silicon) of primary cosmic rays, which reveal different properties from those of light compositions (Helium, Carbon, Oxygen). Here we propose a nearby source scenario, together with the background source contribution, to explain the newly measured spectra of cosmic ray Ne, Mg, Si, and particularly their differences from that of He, C, O. Their differences at high energies can be naturally accounted for by the element abundance of the nearby source. Specifically, the abundance ratio of the nearby source to the background of the Ne, Mg, Si elements is lower by a factor of $\sim1.7$ than that of the He, C, O elements. Such a difference could be due to the abundance difference of the stellar evolution of the progenitor star or the acceleration process/environment, of the nearby source. This scenario can simultaneously explain the high-energy spectral softening features of cosmic ray spectra revealed recently by CREAM/NUCLEON/DAMPE, as well as the energy-dependent behaviors of the large-scale anisotropies. It is predicted that the dipole anisotropy amplitudes below PeV energies of the Ne, Mg, Si group are smaller than that of the He, C, O group, which can be tested with future measurements.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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