Resolving Black Holes: Black Hole Astrophysics in the Era of the Event Horizon Telescope

黑洞是失控的重力，纯粹的引力物体，其特征是其视界--来访的旅行者永远不会回来的不归点。它们还处于现代物理学和天文学的结合点：它们是现代将引力与量子力学相结合的核心，是新兴引力波天文学领域的关键来源，引力波天文学是为宇宙中最明亮的事件提供动力的引擎，并负责推动形成夜空的强大外流。因此，黑洞是了解引力的本质及其在天文学中的过度影响的直接窗口。2017年4月，事件视界望远镜(EHT)，一个地球大小的射电望远镜集合，进行了第一次直接拍摄黑洞地平线图像的观测，为研究它们提供了一个历史性的机会。在接下来的十年里，EHT承诺将以精致的细节揭示地平线附近引力的性质，黑洞是如何通过吸积周围物质而成长的，以及它们如何引发扩大其影响的外流。然而，这需要投资于从即将到来的史无前例的图像中提取这些信息。*我们将继续领导在主要EHT目标的广泛背景下，开发必要的理论模型和分析基础设施，以科学地解释EHT数据。我们已经开始建造和验证强大的分析工具，能够在世界上最大的超级计算机上运行。我们将通过实施减轻已知系统误差的战略来扩大这些措施，使EHT能够最大限度地提高其敏感性。我们还将探索对到目前为止用于解释EHT数据的现有模型集的一些改进，包括对黑洞附近工作的物理过程的越来越详细的描述。最终，这些分析将被用于从EHT观测中产生变革性的科学回报。

Black holes are gravity run amok, purely gravitational objects characterized by their event horizon -- the point of no return from which infalling travelers never return. They also lie at the nexus of modern physics and astronomy: They are central to modern efforts to merge gravity with quantum mechanics, are key sources for the burgeoning field of gravitational wave astronomy, the engines that power the brightest events in the universe, and responsible for driving powerful outflows that shape the night sky. Thus, black holes are a direct window onto the nature of gravity and its inordinate impact in astronomy.******In April, 2017, the Event Horizon Telescope (EHT), an Earth-sized collection of radio telescopes, conducted the first observation that will directly image a black hole horizon, presenting a historic opportunity to study them. Over the next decade, the EHT promises to reveal in exquisite detail the nature of gravity near horizons, how black holes grow by accreting surrounding material, and how they launch the outflows that magnify their impact. However, this requires investment in efforts to extract this information from the unprecedented images that will soon arrive.******We will continue to lead the development of the theoretical models and analysis infrastructure necessary to scientifically interpret EHT data, within the broad context of the primary EHT targets. Already, we have begun the construction and verification of powerful analysis tools, capable of running on the largest supercomputers in the world. We will extend these by implementing strategies to mitigate known systematic errors, enabling the EHT to maximum its sensitivity. We will also explore a number of improvements to the existing set of models used to interpret EHT data thus far, including increasingly detailed descriptions of the physical processes at work near black holes. Ultimately, these analyses will be used to generate transformative scientific returns from the EHT observations.