One of the most promising ways to probe intergalactic magnetic fields (IGMFs) is through gamma rays produced in electromagnetic cascades initiated by high-energy gamma rays or cosmic rays in the intergalactic space. Because the charged component of the cascade is sensitive to magnetic fields, gamma-ray observations of distant objects such as blazars can be used to constrain IGMF properties. Ground-based and space-borne gamma-ray telescopes deliver spectral, temporal, and angular information of high-energy gamma-ray sources, which carries imprints of the intervening magnetic fields. This provides insights into the nature of the processes that led to the creation of the first magnetic fields and into the phenomena that impacted their evolution. Here we provide a detailed description of how gamma-ray observations can be used to probe cosmic magnetism. We review the current status of this topic and discuss the prospects for measuring IGMFs with the next generation of gamma-ray observatories.

中文翻译：

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星系间磁场的伽马射线窗口

探测星系际磁场 (IGMF) 的最有希望的方法之一是通过由星系际空间中的高能伽马射线或宇宙射线引发的电磁级联中产生的伽马射线。由于级联的带电成分对磁场敏感，因此可以使用对遥远物体（如耀变体）的伽马射线观测来限制 IGMF 特性。地基和星载伽马射线望远镜提供高能伽马射线源的光谱、时间和角度信息，这些信息带有干涉磁场的印记。这提供了对导致产生第一个磁场的过程的性质以及影响它们进化的现象的见解。在这里，我们详细描述了如何使用伽马射线观测来探测宇宙磁性。