Collaborative Research: Predicting the Transient Signals from Galactic Centers: Circumbinary Disks and Tidal Disruptions around Black Holes

超大质量黑洞的质量是太阳的数百万到数十亿倍，超大质量黑洞的强大引力影响可以加热附近的气体，使其超过整个银河系的恒星，并以相对论速度向外弹射物质。它们几乎存在于每个大质量星系的中心，它们可能在调节恒星形成速度方面发挥着重要作用。我们的项目旨在为他们所能产生的两个最戏剧性的事件产生到目前为止最真实的模拟：两个轨道上的超大质量黑洞的激发和合并以及恒星的潮汐分裂。两者都曾被认为是不可观测的，但对瞬变敏感的超大型天文观测的出现，导致了无数次潮汐中断的发现，并有望发现许多合并。大量观测数据的前景使这两个问题都成为非常热门的话题。这一计划的最大优势是它提供了将许多现有的研究计划整合到一个更大的科学家、学生和普通公众社区中的机会。它将促进本科生、研究生、博士后研究人员和大学教职员工之间的跨学科合作。塔尔萨大学、约翰·霍普金斯大学、NASA/GSFC和罗切斯特理工学院。通过这样一个网络，我们以前非常成功的外展计划将能够接触到更多、更多样化的受众。例如，S.Noble(PI)将继续与参加月刊俱乐部？的100-200名高中生谈论热门物理话题？这个项目的主要目标是对周双星吸积和潮汐扰动事件的电磁特征做出具体预测，使天文学家能够完全根据EM观测来识别这些壮观的事件，包括使用HST(光学)、JWST(IR)、Chandra(X射线)和ISS-Lobster(X射线)以及地面仪器，如已经运行的全景测量望远镜和快速反应系统，或计划中的大型天气望远镜。这样的识别将极大地帮助我们完善对合并的超大质量黑洞数量的估计，无论是估计潜在引力波目标的数量，还是评估黑洞合并对星系演化的影响。我们对Blue Waters的模拟将采用许多新的计算开发，以实现迄今为止对这些系统的最逼真的模拟。它们包括一个自适应负载均衡器，用于以不均匀的成本均匀分配运行，以及一个多补丁系统，用于在不同的坐标域上演化磁流体动力学方程。我们的目的是使后一种工具公开可用于其他磁流体力学代码。我们的科学成果也将对天体物理界产生广泛的影响，无论是理论上还是观测上。我们将公布详细的光谱和模拟数据，供观察员和未来的任务开发团队使用。这项工作来得特别及时，因为时间域天文学和多信使天文学领域正在迅速发展。

With masses millions to billions times that of our Sun, the strong gravitational influence of supermassive black holes can heat nearby gas so that it outshines an entire galaxy of stars, and slingshot material outward at relativistic speeds. They exist at the centers of almost every massive galaxy, and they may play a significant role in regulating rates of star formation. Our project aims to produce the most realistic simulations to-date of two of the most dramatic events they can make: the inspiral and merger of two orbiting supermassive black holes and the tidal disruption of stars. Both were once thought to be unobservable, but the advent of very large astronomical surveys sensitive to transients have led to the discovery of numerous tidal disruptions and promise the discovery of many mergers. The prospect of extensive observational data make both very hot topics. The great advantage of this program is the opportunity it provides to integrate many existing research programs into a larger community of scientists, students, and the general public. It will foster crossdisciplinary collaborations among undergraduate students, graduate students, postdoctoral researchers and faculty at the Univ. of Tulsa, Johns Hopkins Univ., NASA/GSFC, and Rochester Institute of Technology. Through such a network, our previous highly successful outreach programs will be able to reach an even larger and more diverse audience. For instance, S. Noble (PI) will continue to speak about hot physics topics with the 100-200 high school students that attend the monthly ?Journal Club? event sponsored by his department, and will work with his collaborators on building similar activities at their institutions.The major goal of this project is to make specific predictions of electromagnetic signatures of circumbinary accretion and tidal disruption events that will allow astronomers to identify, based solely on EM observations, these spectacular events using HST (optical), JWST (IR), Chandra (X-ray), and ISS-Lobster (X-ray), as well as ground based instrumentation such as the Panoramic Survey Telescope and Rapid Response System, which is already in operation, or the planned Large Synoptic Survey Telescope. Such identifications will be a tremendous aid in refining our estimates of the population of merging supermassive black holes, both for estimating the numbers of potential gravitational wave targets and for evaluating the impact of black hole mergers on galaxy evolution. Our simulations on Blue Waters will employ a number of new computational developments needed to achieve the most realistic simulations of these systems to date. They include an adaptive load balancer to evenly distribute runs with nonuniform costs, and a multi-patch system for evolving the magnetohydrodynamics equations on different coordinate domains. It is our intent to make the latter tool publicly available for use in other magnetohydrodynamics codes. Our scientific results will also have a wide-reaching impact on the astrophysical community, both theoretically and observationally. We will release detailed spectra and simulation data for use by observers and future mission development teams. This work comes at a particularly opportune time, as the fields of time-domain and multi-messenger astronomy are growing rapidly.