Resolving supermassive black hole binaries and AGN with GRAVITY+

大型星系通过稳定的气体流入以及大小合并的结合而成长。作为星系合并的一部分，人们认为中心的超大质量黑洞相互靠近，最终在新星系的中心形成一个单一的黑洞。然而，流体动力学模拟表明，在大约1秒差距的尺度上，由于角动量和能量去除的经典过程效率低下，合并过程减慢了。然而，在过去的十年里，对秒差距尺度的双星超大质量黑洞（BSMBHs）进行了大量的观测搜索，但几乎没有找到确定的候选者。我们在寻找正确的现象吗？BSMBHs是否有办法有效地绕过秒差尺度的角动量势垒？我们能在AGN人群中识别出他们吗？解决这些问题需要结合最先进的辐射流体动力学模拟和高角度分辨率观测。在这个博士项目中，学生将在理论和观察方面做出前沿项目的贡献，完全符合她在这两个领域的经验。她将对单和双AGN的亚秒差距尺度环境进行新的3D辐射流体动力学模拟（Williamson等人，准备中），以预测可观测到的单和双AGN的区别，并将能够测试她的预测，作为参与VLTI新重力+干涉仪的主机组的一部分。她将成为GRAVITY+科学团队的一员，并为新仪器的主要科学案例之一做出贡献。

Large galaxies grow through a combination of steady inflow of gas as well as major and minor mergers. As part of galaxy mergers, it is thought that the central supermassive black holes approach each other and eventually form a single black hole in the centre of the new galaxy. However, hydrodynamic simulations imply that on scales of about 1 parsec the merging process slows down as classical processes of angular momentum and energy removal are inefficient. Yet, a multitude of observational searches over the last decade for parsec-scale binary supermassive black holes (BSMBHs) came up with fewconfirmed candidates. Are we looking for the right phenomena? Do BSMBHs have a way to effectively bypass the parsec-scale angular momentum barrier? And can we identify them amongst the general AGN population? Solving these questions requires a combination of state-of-the-art radiation hydrodynamical simulations and high angular resolution observations. In this PhD project, the student will contribute to cutting edge projects in both theory and observations, perfectly suiting her experience in both areas. She will work on new 3D radiation hydrodynamical simulations of the sub-parsec-scale environment of single and binary AGN (Williamson et al., in prep) to predict observables differentiating single and double AGN and will be able to test her predictions as part of the host group's involvement in consortium delivering the new GRAVITY+ interferometer at the VLTI. She will become a member of the GRAVITY+ science team and contribute to one of the main science cases of the new instrument.