Outflows from Accreting Black Holes in Active Galactic Nuclei

强风和喷流是活动星系核(AGN)中吸积黑洞的最戏剧性表现之一。最近对吸积流的能量学的研究表明，这种外流不仅是不可避免的，而且质量损失可能如此之大，以至于供应的物质中除了极小一部分之外的所有物质都在到达黑洞之前被排出。这个项目研究了活动星系核中这种新的吸积观点的理论分支和观测结果。尽管质量损失、角动量损失和能量损失以一种可预见的方式相互关联，但外流的具体情况取决于微观物理细节。Begelman博士正在构建“流入-流出”模型，计算它们的辐射特性，并研究它们与相对论喷流的产生和准直的关系，以及它们与活动星系核环境的相互作用。活动星系核中的相对论喷流可能是吸积流内部强大的质量损失的结果之一，但这些喷流也可能从黑洞的自转中获得大量能量。贝格尔曼博士还在研究通过布兰德福德-泽纳耶克效应提取自旋能量的过程如何依赖于黑洞的吸积历史及其当前环境。贝格尔曼博士还在研究布拉德z射线铁线和相对论“盘震学”--研究吸积盘内部区域的受困振荡--作为观测黑洞附近强引力区域的探测器。***

Powerful winds and jets are among the most dramatic manifestations of accreting black holes in active galactic nuclei (AGN). Recent consideration of the energetics of accretion flows suggests that such outflows are not only inevitable, but that the mass loss may be so strong that all but a tiny fraction of the supplied matter is expelled before it reaches the black hole. This project studies the theoretical ramifications and observational consequences of this new view of accretion in AGN. Although the loss of mass, angular momentum, and energy are interrelated in a predictable way, the specifics of the outflows depend on microphysical details. Dr. Begelman is constructing "inflow-outflow" models, calculating their radiative properties, and studying their relationships to the production and collimation of relativistic jets as well as their interactions with the AGN environment.The relativistic jets in AGNs may be one consequence of powerful mass loss from the inner parts of accretion flows, but the jets could also derive much of their energy from the spin of the black hole. Dr. Begelman is also studying how the extraction of spin energy via the Blandford-Znajek effect depends on the black hole's accretion history and its current environment. Dr. Begelman is also studying the braod z-ray iron lines and relativistic "diskoseismology" - the study of trapped oscillations in the inner regions of accretions disks - as observational probes of strong gravity regions close to black holes. ***