A Laser Guide Star Adaptive Optics Study of Stellar Dynamics at the Galactic Center: A Laboratory for Understanding Interactions with a Central Supermassive Black Holes

近年来，利用世界上最大的红外望远镜进行的衍射极限红外观测在我们银河系中心的研究中取得了许多最令人兴奋和重要的突破。 Andrea Ghez和Mark Morris博士（加州大学-洛杉矶分校）将进行一项为期五年的银河系中心研究计划，该计划有三个主要目标：1）获得银河系中心引力势与恒星轨道的精确测量。这将提供一个到银河系中心的距离值，精度超过百分之一，并给出一个极限或一个值，一个黑洞伴侣的质量到银河系中心的超大质量黑洞（SMBH）。这些测定是初步的，并且对于该计划长期研究强引力体系中的广义相对论效应和已经提出存在于那里的扩展暗物质分布是必不可少的，2）使用恒星动力学来区分试图解释SMBH附近令人困惑的年轻恒星存在的理论。这将包括最近在中央秒差距发现的恒星盘中的恒星的偏心率的第一次测量，而没有盘成员的先验假设。类似的测量也将提供强有力的约束，或测量，任何中等质量的黑洞在中心的大质量的年轻星星集群，拱门，和3）测量老年恒星的分布在动态松弛恒星尖为中心的SMBH，以测试模型的恒星动力学和核SMBH的增长。在大多数情况下，本计划所述研究得出的结论也可以应用于其他旋涡星系，从而阐明它们中央SMBH的演化，以及这些SMBH与周围恒星的形成、动力学和命运的相互作用。本计划的一个重要方面是展示激光引导星星自适应光学（LGSAO）的能力，最近才在8到10米级的望远镜上实现。虽然这项技术是未来大型地面望远镜的关键组成部分，但它尚未被天文学界完全接受。此外，拟议工作的各个方面将为未来LGSAO系统的设计和运行提供信息。 在教育方面，该团队将通过为本科生教科书和课程材料、纪录片和博物馆展览制作公开材料并进行公开演讲，广泛传播对公众具有巨大吸引力的银河SMBH及其周围环境的成果。他们还将继续培训和指导大量代表性不足的少数民族，特别是妇女，他们被该计划的成功和Ghez博士鼓励年轻女性进入科学领域的承诺所吸引。

In recent years, diffraction-limited infrared observations with the world's largest infrared telescopes have yielded many of the most exciting and important breakthroughs in the study of the center of our Galaxy. Drs. Andrea Ghez and Mark Morris (University of California - Los Angeles) will conduct a five-year program of Galactic center research which has three primary objectives: 1) Obtain a precision measurement of the Galaxy's central gravitational potential with stellar orbits. This will provide a value of the distance to the Galactic Center to better than one percent accuracy and give a limit or a value for the mass of a black hole companion to the super-massive black hole (SMBH) at the Galactic Center. These determinations are preliminary to, and essential for, this program's long-term investigation of general relativistic effects in the strong gravity regime and of the extended dark matter distribution that has been proposed to exist there, 2) Use stellar dynamics to discriminate between theories attempting to account for the puzzling presence of young stars near the SMBH. This will include the first measurements of eccentricities for stars thought to reside in the stellar disk recently discovered in the central parsec, without the a priori assumption of disk membership. Similar measurements will also provide strong constraints, or measurement, of any intermediate-mass black holes at the center of the massive young star cluster, the Arches, and 3) Measure the distribution of old stars in the dynamically relaxed stellar cusp centered on the SMBH in order to test models of stellar dynamics and of nuclear SMBH growth. The conclusions drawn from the research described in this proposal can, in most cases, be applied to other spiral galaxies as well, thereby elucidating the evolution of their central SMBHs, and the interplay of those SMBHs with the formation, dynamics and fate of their surrounding stars.One important aspect of this project is in demonstrating the power of laser guide star adaptive optics (LGSAO), which has only recently been implemented on 8 to 10 meter-class telescopes. While this technology is a key component of future large ground-based telescopes, it has yet to be fully accepted by the astronomical community. Furthermore, aspects of the proposed work will inform the design and operation of future LGSAO systems. In terms of education, the team will widely disseminate their results on our Galaxy's SMBH and its surroundings, which have tremendous appeal to the general public, by creating publically-available material for undergraduate textbooks and course material, documentaries, and museum exhibits and giving public talks. They will also continue to train and mentor a large number of underrepresented minorities, particularly women, who are attracted to working on this program by its success and the commitment of Dr. Ghez to encouraging young women into science.