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arXiv 2112.04651astro-ph.HEhep-ph
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用超高能漫射$γ$ -射线约束银河系cosmic ray光谱中膝关节的位置

Constraining the position of the knee in the galactic cosmic ray spectrum with ultra-high-energy diffuse $γ$-rays

Pei-pei Zhang, Yi-qing Guo, Bing-qiang Qiao, Wei Liu

摘要:

最近在西藏AS的$γ$实验中测量到了高达$957$ TeV的$γ$射线扩散发射。假设它是由宇宙线核与星际介质之间的强子相互作用产生的,它要求宇宙线核的加速应远远超过PeV能量。目前,对不同物种的宇宙线谱的测量显示出不同的结果。西藏实验表明,质子加氦的谱在PeV以下有一个早期的膝。如果这是正确的话,弥漫的$γ$射线辐射将表明在PeV能量以上的银河宇宙射线的额外成分。这第二个组成部分可能来自最近的超高能$γ$射线观测所揭示的所谓PeVatron的源群,并可能有助于宇宙射线通量达到第二个膝盖的能量。另一方面,KASCADE测量表明质子的膝关节高于PeV。在这种情况下,由西藏天文台观测到的弥散$γ$ -射线可以很好地解释为只有一个宇宙射线成分。这两个人(即。Tibet膝和KASCADE膝)可以通过漫射$γ$射线和宇宙线核的光谱结构来区分。未来HERD和LHAASO实验对单个原子核光谱的测量以及LHAASO对扩散$γ$射线的测量可以共同约束这两种情况。

英文摘要:

The diffuse $γ$-ray emission was measured up to $957$ TeV by the Tibet-AS$γ$ experiment recently. Assuming that it is produced by the hadronic interaction between cosmic ray nuclei and the interstellar medium, it requires that the cosmic ray nuclei should be accelerated well beyond PeV energies. Measurements of the cosmic ray spectra for different species show diverse results at present. The Tibet experiments showed that the spectrum of proton plus helium has an early knee below PeV. If this is correct, the diffuse $γ$-ray emission would suggest an additional component of Galactic cosmic rays above PeV energies. This second component may originate from a source population of so-called PeVatrons revealed by recent ultra-high energy $γ$-ray observations, and could contribute to the cosmic ray fluxes up to the energy of the second knee. On the other hand, the KASCADE measurement showed that the knee of protons is higher than PeV. In this case, the diffuse $γ$-rays observed by Tibet-AS$γ$ can be well accounted for by only one cosmic ray component. These two scenarious (ie. the Tibet and KASCADE knees) could be distinguished by the spectral structures of diffuse $γ$-rays and cosmic ray nuclei. Future measurements of spectra of individual nuclei by HERD and LHAASO experiments and diffuse $γ$-rays by LHAASO can jointly constrain these two scenarios.

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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