We review results from cosmic X-ray surveys of active galactic nuclei (AGNs) over the past $$\approx 15$$≈15 years that have dramatically improved our understanding of growing supermassive black holes in the distant universe. First, we discuss the utility of such surveys for AGN investigations and the capabilities of the missions making these surveys, emphasizing Chandra, XMM-Newton, and NuSTAR. Second, we briefly describe the main cosmic X-ray surveys, the essential roles of complementary multiwavelength data, and how AGNs are selected from these surveys. We then review key results from these surveys on the AGN population and its evolution (“demographics”), the physical processes operating in AGNs (“physics”), and the interactions between AGNs and their environments (“ecology”). We conclude by describing some significant unresolved questions and prospects for advancing the field.

中文翻译：

---

对遥远活动星系的宇宙 X 射线巡天

我们回顾了过去 $$\大约 15$$≈15 年对活动星系核 (AGN) 的宇宙 X 射线调查结果，这些结果极大地提高了我们对遥远宇宙中不断增长的超大质量黑洞的理解。首先，我们讨论此类调查对 AGN 调查的效用以及进行这些调查的任务的能力，重点是 Chandra、XMM-Newton 和 NuSTAR。其次，我们简要描述了主要的宇宙 X 射线巡天、互补多波长数据的基本作用以及如何从这些巡天中选择 AGN。然后，我们回顾了这些关于 AGN 种群及其演化（“人口统计学”）、在 AGN 中运行的物理过程（“物理学”）以及 AGN 与其环境之间的相互作用（“生态”）的调查的主要结果。