The existence of a “knee” at energy $\sim 1\mathrm{PeV}$ in the cosmic-ray spectrum suggests the presence of Galactic PeV proton accelerators called “PeVatrons.” Supernova remnant (SNR) $\mathrm{G}106.3+2.7$ is a prime candidate for one of these. The recent detection of very high energy (0.1–100 TeV) gamma rays from $\mathrm{G}106.3+2.7$ may be explained either by the decay of neutral pions or inverse Compton scattering by relativistic electrons. We report an analysis of 12 years of Fermi-LAT gamma-ray data that shows that the GeV-TeV gamma-ray spectrum is much harder and requires a different total electron energy than the radio and x-ray spectra, suggesting it has a distinct, hadronic origin. The nondetection of gamma rays below 10 GeV implies additional constraints on the relativistic electron spectrum. A hadronic interpretation of the observed gamma rays is strongly supported. This observation confirms the long-sought connection between Galactic PeVatrons and SNRs. Moreover, it suggests that $\mathrm{G}106.3+2.7$ could be the brightest member of a new population of SNRs whose gamma-ray energy flux peaks at TeV energies. Such a population may contribute to the cosmic-ray knee and be revealed by future very high energy gamma-ray detectors.

中文翻译：

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来自 SNRG106.3+2.7 的 Fermi-LAT 观测的 PeV 质子加速证据

能量“膝盖”的存在$～1\mathrm{电动汽车}$在宇宙射线光谱中表明存在称为“PeVatrons”的银河 PeV 质子加速器。超新星遗迹（SNR）$\mathrm{G}106.3+2.7$是其中之一的主要候选人。最近探测到的非常高能（0.1-100 TeV）的伽马射线来自$\mathrm{G}106.3+2.7$可以通过中性介子的衰变或相对论电子的逆康普顿散射来解释。我们报告了对 12 年 Fermi-LAT 伽马射线数据的分析，该数据表明 GeV-TeV 伽马射线光谱比无线电和 X 射线光谱更难，并且需要不同的总电子能量，这表明它具有独特的，强子起源。未检测到低于 10 GeV 的伽马射线意味着对相对论电子光谱的额外限制。强烈支持对观测到的伽马射线的强子解释。这一观察证实了银河 PeVatron 和 SNR 之间长期寻求的联系。此外，它表明$\mathrm{G}106.3+2.7$可能是新的 SNR 群体中最亮的成员，其伽马射线能量通量在 TeV 能量处达到峰值。这样的种群可能对宇宙射线拐点有贡献，并被未来的超高能伽马射线探测器揭示出来。