Precision Measurements of the Black-Hole Properties in the Center of the Milky Way

银河系中心的黑洞SgrA*是我们银河系中所有已知黑洞中质量最大的。也是目前宇宙中距离最近的超大质量黑洞。这种大质量和小距离的组合使SGR A*成为强场条件下高能和引力天体物理的终极试验台。在不久的将来，仪器设备的重大发展将通过观测恒星轨道上的相对论效应、脉冲星的计时以及其吸积流的水平尺度图像，为高精度研究其时空提供工具。在拟议的研究项目中，PI和他的合作者将研究可能限制用每种技术精确测量黑洞性质的天体物理复杂性，并设计出克服这些复杂性的方法。这项工作将使他们能够利用NSF在技术上的投资，如Event Horizon Telescope和GBT，以及通过NSF-MRI奖在亚利桑那大学建造基于GPU的计算机集群。在拟议的项目中，一名研究生将接受预测天体物理黑洞的强场性质和实施统计工具分析未来数据的培训。通过在拟议项目期间组织跨学科科学会议，私营部门和COPI还致力于在科学界更广泛地传播研究活动。他们还致力于通过非技术性的公开讲座和演示向公众传播科学成果。

The black hole in the center of the Milky Way, Sgr A*, is the most massive among all the known black holes in our galaxy. Is also by far the closest among all the supermassive black holes in the universe. This combination of a large mass and a small distance makes Sgr A* the ultimate test-bed of high-energy and gravitational astrophysics in the strong field regime. In the near future, major developments in instrumentation will provide the tools for high-precision studies of its space-time via observations of relativistic effects in stellar orbits, in the timing of pulsars, and in horizon-scale images of its accretion flow.In the proposed research project, the PI and his collaborators will investigate the astrophysical complexities that may limit precise measurements of the black-hole properties with each technique and devise ways to overcome them. This work will allow them to capitalize on the NSF investment in technologies, such as the Event Horizon Telescope and the GBT, as well as on the construction of a GPU-based computer cluster at the University of Arizona that became possible through an NSF-MRI award.During the proposed project, one graduate student will be educated in predicting the strong-field properties of astrophysical black holes and in implementing statistical tools for analyzing future data. The PI and CoPI are also committed to the broader dissemination of the research activities in the scientific community by organizing interdisciplinary scientific conferences during the time of the proposed project. They are also engaged in communicating the scientific results to the general public via non-technical public lectures and demonstrations.