A simplified global solution for an advection-dominated accretion flow

	A simplified global solution for an advection-dominated accretion flow
	Yuan, Feng; Ma, Renyi; Narayan, Ramesh
刊名	ASTROPHYSICAL JOURNAL
	2008-06-01
卷号	679 期号:2 页码:984-989
关键词	accretion accretion disks black hole physics galaxies : active galaxies : nuclei hydrodynamics
英文摘要	When we model black hole accretion sources such as active galactic nuclei and black hole X-ray binaries as advection-dominated accretion flows (ADAFs), it is necessary to use the global solution to the equations rather than the simpler self-similar solution, since the latter is inaccurate in the region near the black hole where most of the radiation is emitted. However, technically, it is a difficult task to calculate the global solution because of the transonic nature of the flow, which makes it a two-point boundary value problem. In this paper we propose a simplified approach for calculating the global ADAF solution. We replace the radial momentum equation by a simple algebraic relation between the angular velocity of the gas and the Keplerian angular velocity while keeping all other equations unchanged. It is then easy to solve the differential energy equations to obtain an approximate global solution. By adjusting the free parameters, we find that for almost any accretion rate and for alpha = 0.1-0.3 we can get good simplified global solutions. The predicted spectra from the approximate solutions are very close to the spectra obtained from the true global solutions.
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]	SAGITTARIUS-A-ASTERISK ; SLIM-DISK MODEL ; X-RAY BINARIES ; BLACK-HOLE ; ELECTRONS ; SPECTRUM ; STATES
收录类别	SCI
语种	英语
WOS记录号	WOS:000256315500005
公开日期	2010-11-08
内容类型	期刊论文
源URL	[http://119.78.226.72//handle/331011/12643]
专题	上海天文台_星系宇宙学重点实验室
作者单位	Chinese Acad Sci, Shanghai Astron Observ, Shanghai 200030, Peoples R China
推荐引用方式 GB/T 7714	Yuan, Feng,Ma, Renyi,Narayan, Ramesh. A simplified global solution for an advection-dominated accretion flow[J]. ASTROPHYSICAL JOURNAL,2008,679(2):984-989.
APA	Yuan, Feng,Ma, Renyi,&Narayan, Ramesh.(2008).A simplified global solution for an advection-dominated accretion flow.ASTROPHYSICAL JOURNAL,679(2),984-989.
MLA	Yuan, Feng,et al."A simplified global solution for an advection-dominated accretion flow".ASTROPHYSICAL JOURNAL 679.2(2008):984-989.