Exploration of sources of ultra high-energy cosmic rays with GeV-TeV gamma-ray observations

超高能宇宙射线（UHECR）的来源是未知的。在加速场中，高能质子可以与周围物质/光子相互作用，并发射出GeV-TeV的伽马射线。最近费米卫星或切伦科夫望远镜发现了新的伽马射线源。我开发了一个代码来模拟级联过程中的加速网站，并成功地提高了这一点，可以按照时间演变在本研究期间。通过与观测结果的比较，我们研究了γ射线源作为可能的加速场。特别是来自伽玛射线暴（GRB）的GeV伽玛射线是强子辐射的有希望的候选者。作为费米小组的一员，我对伽玛暴发射机制的探索做出了巨大贡献。不幸的是，目前可用的伽马射线数据在统计上不足以揭示UHECR的来源。但是，从我们的结果的基础上，我们已经开发的代码，我们发现特征谱的强子发射的演变。这是一个重要的结果，可以通过CTA等未来观测进行验证，这将确定UHECR的来源。

The sources of ultra high-energy cosmic rays (UHECRs) are unknown. In acceleration sites, high-energy protons can interact with ambient matters/photons, and emit characteristic GeV-TeV gamma-rays. Recently Fermi satellite or Air Cherenkov Telescopes have discovered new gamma-ray sources. I developed a code to simulate cascade processes in the acceleration sites, and succeeded in improving this to one that can follow temporal evolution in this research period. By comparing our results with observations, we have studied gamma-ray sources as possible acceleration sites. Especially, GeV gamma-rays from gamma-ray bursts (GRBs) are promising candidates of hadronic emissions. I have greatly contributed to exploration of the emission mechanism of GRBs as a member of the Fermi team. Unfortunately, the present available data of gamma-rays are not statistically enough to reveal the sources of UHECRs. But, from our results based on the code we have developed, we found characteristic spectral evolutions in hadronic emissions. This is an important result that can be verified with future observations such as CTA, which will determine the sources of UHECRs.