Two kinds of Galactic source populations could explain the cosmic-ray observation up to the "knee" region
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arXiv
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| Autori principali: | , , , |
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| Natura: | Preprint |
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2026
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| _version_ | 1866909054145658880 |
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| author | Li, Furong Liu, Wei Shao, Yali Guo, Yi-Qing |
| author_facet | Li, Furong Liu, Wei Shao, Yali Guo, Yi-Qing |
| contents | Observations of diffuse gamma rays above hundreds of TeV from the Galactic disk provide strong evidence for the existence of PeV cosmic-ray accelerators--so-called PeVatrons--in the Galaxy. However, mounting observations have ruled out most supernova remnants as likely PeVatron candidates, suggesting instead that multiple populations of cosmic-ray sources exist in the Galaxy. Recently, the LHAASO collaboration reported the detection of ultra-high-energy gamma rays from microquasars, establishing that the black holes in these systems, which accrete matter from companion stars, are powerful PeV particle accelerators. In this work, we propose a two-component source model to explain the observed cosmic-ray spectra and composition up to the PeV range. Below approximately 100 TeV, supernova remnants serve as the dominant sources; above this energy, microquasars are considered the primary candidate population. Within this scenario, the assumption of a charge-dependent cutoff well accounts for the latest measurements, including the proton and helium spectra up to the PeV range, the energy-dependent composition, and the all-particle spectrum. In contrast, the nuclei-dependent cutoff hypothesis is ruled out by the data. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2605_18266 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Two kinds of Galactic source populations could explain the cosmic-ray observation up to the "knee" region Li, Furong Liu, Wei Shao, Yali Guo, Yi-Qing High Energy Astrophysical Phenomena Observations of diffuse gamma rays above hundreds of TeV from the Galactic disk provide strong evidence for the existence of PeV cosmic-ray accelerators--so-called PeVatrons--in the Galaxy. However, mounting observations have ruled out most supernova remnants as likely PeVatron candidates, suggesting instead that multiple populations of cosmic-ray sources exist in the Galaxy. Recently, the LHAASO collaboration reported the detection of ultra-high-energy gamma rays from microquasars, establishing that the black holes in these systems, which accrete matter from companion stars, are powerful PeV particle accelerators. In this work, we propose a two-component source model to explain the observed cosmic-ray spectra and composition up to the PeV range. Below approximately 100 TeV, supernova remnants serve as the dominant sources; above this energy, microquasars are considered the primary candidate population. Within this scenario, the assumption of a charge-dependent cutoff well accounts for the latest measurements, including the proton and helium spectra up to the PeV range, the energy-dependent composition, and the all-particle spectrum. In contrast, the nuclei-dependent cutoff hypothesis is ruled out by the data. |
| title | Two kinds of Galactic source populations could explain the cosmic-ray observation up to the "knee" region |
| topic | High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2605.18266 |