Abstract Recent results in the field of high energy active galactic nuclei (AGN) astrophysics, benefiting from improvements to gamma-ray instruments and observational strategies, have revealed a surprising wealth of unexpected phenomena. These developments have been brought about both through observational efforts to discover new very high energy gamma-ray emitters, as well as from further in-depth observations of previously detected and well studied objects. I here focus specifically on the discovery of repeated temporal structures observed in AGN lightcurves, and new hard spectral components within the spectral energy distributions of other AGN systems. The challenges that these new features place on the modeling of the sources are highlighted, along with some reflections on what these results tell us about the underlying nature of the emission processes at play.

中文翻译：

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伽马射线视角下的活动星系核视界

摘要 得益于伽马射线仪器和观测策略的改进，高能活动星系核 (AGN) 天体物理学领域的最新成果揭示了大量意想不到的现象。这些发展是通过发现新的超高能伽马射线发射器的观测努力以及对先前检测到并经过充分研究的物体的进一步深入观察而实现的。我在这里特别关注在 AGN 光曲线中观察到的重复时间结构的发现，以及其他 AGN 系统的光谱能量分布中的新硬光谱分量。强调了这些新功能对源建模的挑战，