On the origin of X-ray emission in some FR I galaxies: ADAF or jet?

	On the origin of X-ray emission in some FR I galaxies: ADAF or jet?
	Wu, Qingwen ; Yuan, Feng; Cao, Xinwu
刊名	ASTROPHYSICAL JOURNAL
	2007-11-01
卷号	669 期号:1 页码:96-105
关键词	accretion accretion disks galaxies : active galaxies : nuclei X-rays : galaxies
英文摘要	We investigate the origin of X-ray emission in FR I galaxies using radio, submillimeter, optical, and Chandra X-ray data for a small sample of eight FR I sources. These sources are very dim, with X-ray luminosities L(X)/L(Edd) similar to 10(-4) to 10(-8) (with L(X) the X-ray luminosity between 2 and 10 keV). We try to fit the multi-wave-band spectra using a coupled accretion-jet model. In this model, the accretion is described by an advection-dominated accretion flow (ADAF); in the innermost region of the ADAF, a fraction of the flow is transferred into the vertical direction and forms a jet. We find that X-ray emission in the source with the highest L(X) (similar to 1.8 x 10(-4) L(Edd)) is from the ADAF. The results for the four sources with moderate L(X) (several times 10(-6) L(Edd)) are complicated. Two are dominated by the ADAF, one by the jet, and the other by the sum of the jet and ADAF. The X-ray emission in the three least luminous sources ( L(X) less than or similar to 1.0 x 10(-6) L(Edd)) is mainly from the jet, although for one source it can also be interpreted as the ADAF, since the quality of the X-ray data is low. We conclude that these results roughly support the prediction of Yuan & Cui that when the X-ray luminosity of a system is below some critical value, the X-radiation will not be dominated by the emission from the ADAF any longer, but by the jet. We also investigate the fuel supply in these sources. We find that the accretion rate in four of the five sources for which we have good constraints must be higher than the Bondi rate. This implies that another fuel supply, such as gas released by the stellar population inside the Bondi radius, should be important.
学科主题	星系与宇宙学研究中心
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	INEFFICIENT ACCRETION FLOW ; ACTIVE GALACTIC NUCLEI ; BLACK-HOLE ACCRETION ; ADVECTION-DOMINATED ACCRETION ; RADIO-GALAXIES ; FUNDAMENTAL PLANE ; CHANDRA OBSERVATIONS ; VLBI OBSERVATIONS ; COMPLETE SAMPLE ; QUIESCENT STATE
收录类别	SCI
语种	英语
WOS记录号	WOS:000250480600009
公开日期	2010-11-08
内容类型	期刊论文
源URL	[http://119.78.226.72//handle/331011/12613]
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, Shanghai Astron Observ, Joint Inst Galaxy & Cosmol, Shanghai 200030, Peoples R China 2.Univ Sci & Technol China, Shanghai 200030, Peoples R China 3.Korea Astron & Space Sci Inst, Taejon 305348, South Korea
推荐引用方式 GB/T 7714	Wu, Qingwen,Yuan, Feng,Cao, Xinwu. On the origin of X-ray emission in some FR I galaxies: ADAF or jet?[J]. ASTROPHYSICAL JOURNAL,2007,669(1):96-105.
APA	Wu, Qingwen,Yuan, Feng,&Cao, Xinwu.(2007).On the origin of X-ray emission in some FR I galaxies: ADAF or jet?.ASTROPHYSICAL JOURNAL,669(1),96-105.
MLA	Wu, Qingwen,et al."On the origin of X-ray emission in some FR I galaxies: ADAF or jet?".ASTROPHYSICAL JOURNAL 669.1(2007):96-105.