利用吸收线光变研究类星体外流的物理性质

Active galactic nucleus outflows carry a large amount of matter and energy into the surrounding environment and have long been considered a potential key factor in regulating the growth of SMBH and the evolution of their host galaxies. The galactocentric distance (R) is crucial for understanding the outflow's origin and its influence on the galaxy evolution. Over the past ~20 years, R has been measured for only tens of individual quasars using density-sensitive absorption lines from excited levels (e.g. S iv*, Fe ii*), which is regarded as the most reliable strategy among conventional methods. Due to line blending, however, this method cannot be applied on broad absorption line (BAL) outflows. From a new perspective, based on the statistical properties of C IV BAL variability, we have successfully derived the distribution of R and the kinetic luminosities of outflows in a sample of ~1000 quasars. This result has demonstrated the power of this new strategy, and many more possibilities are awaited to be explored. We plan on developing a whole suite of new methods based on BAL variability, which will help deepen our understanding of the spatial distribution, velocity structure and ionization structure of outflows, and consequently shed light on their origin, their acceleration process, and their effects on galaxy evolution.

活动星系核外流将大量物质和能量从星系核区携带至寄主星系中,因而一直被认为是影响超大质量黑洞与寄主星系共同演化的潜在的重要因素。外流的尺度是理解外流起源、衡量外流对星系环境影响的关键参数之一。传统上认为利用密度依赖的离子激发态吸收线(如Siv*,Feii*等)测定外流尺度的方法较为可靠，但该方法只适用于没有自混合的较窄吸收线,对于典型的宽吸收线外流则无能为力。二十多年来,人们用该方法只成功测量了数十个外流的尺度。着眼于CIV宽吸收线光变的统计性质这一新视角，我们最近提出全新的方法，给出了近千个宽吸收线外流的尺度和动力学光度的分布。这一阶段性成果证明基于吸收线光变测定外流尺度的思路具有很大潜力，亟待我们进一步开发具体方法，逐渐形成一整套有力的工具，使我们对外流气体的空间分布、速度结构、电离结构等各方面的系统性分析成为可能，从而进一步深化对外流的起源和加速过程以及其对星系演化影响的认识。

外流是活动星系核反馈的主要形式之一。但外流的反馈是否有效，如有效，其反馈是正还是负一直是星系演化领域中最受关注的争议之一。吸收线光变是研究外流物理的最有力手段之一。在本项目的支持下，取得了一系列重要的科学进展。主要有下：1，系统性地建立利用光变测量外流物理性质的方法，并发现高速外流在百光年尺度上的加速现象，远超经典黑洞-吸积盘盘风预言的尺度（Science Advances 8, eabk3291, 2022）；2，利用斯隆大样本巡天数据，首次发现活动星系演化进程中恒星形成率的反弹现象，揭示超大质量黑洞驱动的外流对星系演化的负反馈作用, 发表于Nature Astronomy(入选ESI top1%高引)。3，首次发现黑洞潮汐撕裂事件中光学铁发射线的迟滞效应，揭示铁线可能产生于尘埃的升华面的新起源，发表于ApJL. 其他相关成果共计15篇，均发表于国际著名的学术期刊。项目负责人在该项目之后，继续获得优秀青年科学基金的支持。