活动星系核中的尘埃  

Dust in active galactic nuclei

作　　者：王慕鹭 李爱根[2] 向福元[1] 唐翌[1] 钟建新[1] 

机构地区：[1]湘潭大学材料与光电物理学院,湘潭411105 [2]密苏里大学物理与天文学系

出　　处：《中国科学：物理学、力学、天文学》2014年第8期771-782,共12页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：美国国家科学基金(编号:AST-1109039);美国宇航局科学基金(编号:NNX13AE63G);国家自然科学基金(批准号:11173019;11273022)资助项目

摘　　要：尘埃是活动星系核统一模型的基石,该模型认为呈现不同观测特征的活动星系核在物理本质上属于同一类天体,活动星系核外围绕着一个光学厚尘埃环,不同类型的活动星系核只是因观测者视线相对于活动星系核对称轴的取向不同而已.观测表明,活动星系核中尘埃的组成成分及尺寸与银河系星际尘埃有很大的差别.本文介绍活动星系核核周尘埃的消光和红外辐射以及尘埃可能的化学组成和尺寸分布的研究现状.Dust is the cornerstone of the unification theory of active galactic nuclei （AGNs）. This theory proposes that all AGNs are essentially ＂born equal＂： all types of AGNs are surrounded by an optically thick dust torus and are basically the same object but viewed from different lines of sight. The large diversity in the observational properties of AGNs is simply caused by the viewing-angle-dependent obscuration of the nucleus： those viewed face-on are unobscured （allowing for a direct view of their nuclei） and recognized as ＂type 1＂ AGNs, while those viewed edge-on are ＂type 2＂ AGNs with most of their central engine and broad line regions being hidden by the obscuring dust. However, little is known about the dust in the circumnuclear torus of AGNs. There is evidence suggesting that the size and composition of the dust in AGNs may differ substantially from that of the Galactic interstellar dust, as reflected by the flat ＂gray＂ extinction curves, the 2175 A extinction bump is not （or at least rarely） seen in AGNs, and the anomalous silicate emission or absorption features observed respectively in type 1 and type 2 AGNs. This review summarizes our current understanding of the extinction and infrared emission properties of the circumnuclear dust in AGNs as well as the inferred dust composition and size distribution.

关 键 词：活动星系核 尘埃 发射 消光 硅酸盐 

分 类 号：P157[天文地球—天文学]