On the convective instability of hot radiative accretion flows

	On the convective instability of hot radiative accretion flows
	Yuan, Feng1 ; Bu, De-Fu 1,2
刊名	MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
	2010-10-21
卷号	408 期号:2 页码:1051-1060
关键词	accretion black hole physics hydrodynamics ISM: jets and outflow accretion discs
英文摘要	An important question is what fraction of gas available at the outer boundary can finally fall on to the black hole. This determines the observational appearance of accretion flows, and is also related to the evolution of black hole mass and spin. Previous two-dimensional hydrodynamical simulations of hot accretion flows have found that the flow is convectively unstable because of its inward increase of entropy. As a result, the mass accretion rate decreases inward (i.e. only a small fraction of accretion gas can fall on to the black hole), while the rest circulates in the convective eddies or is lost in convective outflows. Radiation is usually neglected in these simulations. In many cases, however, radiative cooling is important. In the regime of the luminous hot accretion flow (LHAF), radiative cooling is even stronger than the viscous dissipation. In the one-dimensional case, this implies that the inward increase of entropy will become slower, or the entropy even decreases inward in the case of an LHAF. We therefore expect the convective instability to become weaker or completely disappear when radiative cooling is important. To examine the validity of this expectation, in this paper we perform two-dimensional hydrodynamical simulations of hot accretion flows with strong radiative cooling. We find that, compared to the case of negligible radiation, convection only becomes slightly weaker. Even an LHAF is still strongly convectively unstable, and its radial profile of accretion rate correspondingly changes little. We find the reason is that the entropy still increases inward in the two-dimensional case.
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	ADVECTION-DOMINATED ACCRETION ; X-RAY SOURCES ; BLACK-HOLES ; ANGULAR-MOMENTUM ; SAGITTARIUS-A ; 2 DIMENSIONS ; DISKS ; CONDUCTION ; STABILITY ; TRANSPORT
收录类别	SCI
语种	英语
WOS记录号	WOS:000282639100030
公开日期	2011-06-29
内容类型	期刊论文
源URL	[http://119.78.226.72//handle/331011/13375]
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, Key Lab Res Galaxies & Cosmol, Shanghai 200030, Peoples R China 2.Chinese Acad Sci, Grad Sch, Beijing 100039, Peoples R China
推荐引用方式 GB/T 7714	Yuan, Feng,Bu, De-Fu. On the convective instability of hot radiative accretion flows[J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,2010,408(2):1051-1060.
APA	Yuan, Feng,&Bu, De-Fu.(2010).On the convective instability of hot radiative accretion flows.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,408(2),1051-1060.
MLA	Yuan, Feng,et al."On the convective instability of hot radiative accretion flows".MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 408.2(2010):1051-1060.