DUST IN ACTIVE GALACTIC NUCLEI: ANOMALOUS SILICATE TO OPTICAL EXTINCTION RATIOS?

	DUST IN ACTIVE GALACTIC NUCLEI: ANOMALOUS SILICATE TO OPTICAL EXTINCTION RATIOS?
	Lyu, Jianwei 1,2; Hao, Lei1 ; Li, Aigen 2
刊名	ASTROPHYSICAL JOURNAL LETTERS
	2014-09-01
卷号	792 期号:1 页码:9-13
关键词	dust galaxies: active galaxies: ISM infrared: galaxies extinction
通讯作者	郝蕾
英文摘要	Dust plays a central role in the unification theory of active galactic nuclei (AGNs). However, little is known about the nature (e.g., size, composition) of the dust that forms a torus around the AGN. In this Letter, we report a systematic exploration of the optical extinction (A(V)) and the silicate absorption optical depth (Delta tau(9.7)) of 110 type 2 AGNs. We derive A(V) from the Balmer decrement based on the Sloan Digital Sky Survey data, and Delta tau(9.7) from the Spitzer/InfraRed Spectrograph data. We find that with a mean ratio of < A(V)/Delta tau(9.7)> less than or similar to 5.5, the optical-to-silicate extinction ratios of these AGNs are substantially lower than that of the Galactic diffuse interstellar medium (ISM) for which A(V)/Delta tau(9.7) approximate to 18.5. We argue that the anomalously low A(V)/Delta tau(9.7) ratio could be due to the predominance of larger grains in the AGN torus compared to that in the Galactic diffuse ISM.
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	DIGITAL SKY SURVEY ; STAR-FORMING GALAXIES ; MU-M ; INTERSTELLAR EXTINCTION ; RED QUASARS ; X-RAY ; EMISSION ; AGN ; ABSORPTION ; GRAINS
收录类别	SCI
语种	英语
WOS记录号	WOS:000341306900009
公开日期	2015-02-14
内容类型	期刊论文
源URL	[http://119.78.226.72//handle/331011/15746]
专题	上海天文台_星系宇宙学重点实验室
作者单位	1.Chinese Acad Sci, Key Lab Res Galaxies & Cosmol, Shanghai Astron Observ, Shanghai 200030, Peoples R China 2.Univ Missouri, Dept Phys & Astron, Columbia, MO 65211 USA
推荐引用方式 GB/T 7714	Lyu, Jianwei,Hao, Lei,Li, Aigen. DUST IN ACTIVE GALACTIC NUCLEI: ANOMALOUS SILICATE TO OPTICAL EXTINCTION RATIOS?[J]. ASTROPHYSICAL JOURNAL LETTERS,2014,792(1):9-13.
APA	Lyu, Jianwei,Hao, Lei,&Li, Aigen.(2014).DUST IN ACTIVE GALACTIC NUCLEI: ANOMALOUS SILICATE TO OPTICAL EXTINCTION RATIOS?.ASTROPHYSICAL JOURNAL LETTERS,792(1),9-13.
MLA	Lyu, Jianwei,et al."DUST IN ACTIVE GALACTIC NUCLEI: ANOMALOUS SILICATE TO OPTICAL EXTINCTION RATIOS?".ASTROPHYSICAL JOURNAL LETTERS 792.1(2014):9-13.