Collaborative Research: Predicting the Observational Signatures of Accreting Black Holes

由于黑洞(BH)的定义是不可见的，天文学家探测它们的唯一方法是观察附着在黑洞上(或掉进黑洞中)的物质。考虑到黑洞附近强大的引力、强烈的辐射和强大的磁场，这种吸积是复杂的，只有在超级计算机上运行复杂的数值模型才能理解。伊利诺伊大学、普林斯顿大学和加州大学伯克利分校之间的一项研究合作将在强吸积和弱吸积之间建立BH吸积行为的模型，当已知发生有趣的效应时，如外流物质的喷射和吸积中的异常振荡。这项工作将有助于揭开与黑洞有关的谜团，例如喷流是如何形成的，吸积流的结构是如何随着时间的推移而变化的。该团队将通过讲座和可视化向公众传达黑洞天体物理学的兴奋之处，并通过黑洞暑期学校向未来几代学生传达。黑洞(BH)吸积和流出理论是现代天体物理和引力物理许多领域的核心。合作小组已经开发出数值技术，可以对高吸积率和低吸积率极限下的黑洞吸积进行近乎从头计算的建模。该团队计划开发新的数值技术和代码，适用于研究困难的中等吸积率区域，这与喷流、准周期振荡和恒星质量黑洞周围的状态转换有关。模型中增加了辐射力、对的产生和传输、非热粒子的产生和传输以及无碰撞的等离子体效应，所有这些对于在黑洞天体物理学的长期问题上取得进展都是至关重要的，例如中等吸积率的吸积的结构和观测外观(光谱、时间变异性、极化)，以及有关大型磁场的起源和维持的问题，据信这些磁场为来自此类系统的相对论喷流提供动力。该组织将通过公开发布，将他们的新代码提供给其他人使用。

Since black holes (BH) are by definition invisible, the only way that astronomers can detect them is by observing material accreting onto (or falling into) the black hole. Given the strong gravity, intense radiation and powerful magnetic fields near black holes, it is not surprising that such accretion is complex and can only be understood by running sophisticated numerical models on supercomputers. A research collaboration between the University of Illinois, Princeton University and the University of California-Berkeley will model the behavior of BH accretion in the realm intermediate between strong and weak accretion, when interesting effects such as jets of outflowing material and unusual oscillations in the accretion are known to take place. This work will help to unravel mysteries related to black holes, such as how the jets form and how the structure of the accretion flow changes over time. The team will communicate the excitement of black-hole astrophysics to the public through lectures and visualizations, and to future generations of students through a black hole summer school.The theory of black-hole (BH) accretion and outflows is central to many areas of modern astrophysics and gravitational physics. The collaboration team has developed numerical techniques that permit nearly ab initio modeling of black-hole accretion in both the high- and low-accretion-rate limits. The team plans to develop new numerical techniques and codes suitable for studying the difficult, intermediate-accretion-rate regime, which is associated with jets, quasi-periodic oscillations, and state transitions around stellar-mass black holes. Additions to the models include radiation forces, pair production and transport, nonthermal particle production and transport, and collisionless plasma effects, all of which are critical for making progress on long-standing problems in black-hole astrophysics, such as the structure and observational appearance (spectrum, time variability, polarization) of accretion at intermediate accretion rates, as well as questions about the origin and maintenance of large-scale magnetic fields believed to power relativistic jets from such systems. The group will make their new codes available for others to use through public releases.