Outflow influences on RIAF: dynamical aspects Fu-Guo Xie, Feng Yuan Shanghai Astronomical Observatory fgxie@shao.ac.cn

outline Introduction ADAF with Outflow Discussions. 1,Observational Clues on Outflows. 2,previous theoretical models on ADAF & Outflow. ADAF with Outflow 1, basic idea and the governing equations. 2, results Discussions.

Introduction: Mass loss phenomenon of the disk may be commonly presented in accreting discs and thus a small fraction of gases can actually falls on to the BH: e.g.: 1, Broad/Narrow Absorption Line Quasars shows high velocity outflows (Blandford & Begelman (’99)). 2, X-ray obs. indicates that Sgr A* has mdot about 10-5 msun/y (Baganoff et al. '03), which is too large to produce radio linear polarization (Quataert & Gruzinov,'00; Agol '00) Outflow may serve as an feedback on galaxy formation, accretion(Silk & Rees 1998;Springel et al. 2005)

MHD simulation of Adiabatic Flow. Proga, '03

MHD simulation of Adiabatic Flow. Proga, '03 Stone et al. '99

Introduction:theoretical models been investigated Various models proposed recently(Xu & Chen('97), Blandford & Begelman('99), Beckert('00), Misra & Taam('01), Xue & Wang ('05), Tanka & Menou('06) ...) ; Numerous simulations are carried out, both hydrodynamically(Stone et al. '99; Blandford & Begelman, '04 ) or MagnetoHydrodynamically(Proga, '03; Igumenshchev, et al., '99, '00, '01; Stone et al. '01; Hawley & Balbus '02; Mckinney & Gammie, '04; Villiers & Hawley, et al.,'05...).

→ How to consider outflow’s effect? usually introduce constant p, (e.g. Quataert, Narayan ('99)) to present mass loss rate, which may be controvisal (e.g. Yuan et al. '05) usually, extra angular momentum draw from accretion disk by outflow is neglected. (See Blandford & Begelman(’04), But see Blandford, Begelman ('99)); → How to consider outflow’s effect?

Schematic view Assumptions In Accretion Flow: In Outflow: vz neglected, no vertical momentum, thus, hydrostatical equilibrium achieved. (e.g. Manmoto et al ’97) no vertical difference in vr, v , cs In Outflow: vertical velocity exist. vrw considered outward. outflow has different T, compared to accretion flow. After these assumptions, we height integrate the basic fluid equations…

Basic Equations. in cylinder coordinate outflow intensity mass equation B&B : m_dot ～ rp0 radial equation angular equation energy equation

Parameters similar to evaporation, greater c_s will subsequently cause v_z,w v_r,w should be comparable to v_ff z : Blandford &Begelman ('99) implies 0 p0 <1 ,to have mass loses and energy increases as gas accreting to the central object. Similarly, here: 0 z <|vr|/1/cs0.2  : B&B also denote that lw > l , if any magnetic coupling to the disc; while Beckert('00) argues that magnetically driven outflow prefers the lw < l, which is supported in Xu & chen ('97), Narayan,Yi('95), B&B('04, if outflow orginates from the surface) T : Usually we have Tw > T ,as corona indicates; however, Tw < T can also be possible, such as stellar winds from massive stars in young clusters. We apply Ti,w Ti, Te,w > Te with assumptions that ions are much harder to heat.

Parameters : analysis This seems most significant, if mass loss is efficient and Te,w vary a lot from Te

Solutions : 1-T self-similar vr,w = vr cs, vr,v  vk, mdot rp0

Solutions: Comparation Vrw = Vr f = 1.0 Ti,e = 1.0 p0=0.477 min/msupply=0.13 Compare with previous work(e.g. Quataert et al; Yuan et al; ...) on the same net-accretion-mass

=0.9 z=0.1 Ti=1.0 Te=1.5 ～

=0.9 z=0.1 Ti=1.0 Te=1.5 ～

r=0.1 z=0.1 Ti=1.0 Te=1.5

r=0.1 z=0.1 Ti=1.0 Te=1.5

=1.0 z=0.1 Ti=1.0 Vr,w=Vr

=1.0 z=0.1 Ti=1.0 Vr,w=Vr

Primary conclusions On most occasions, outflow will reshape the m_dot function to make it vary rapidly at outer region, and slower at inner region; If outflow carries more angular momentum, the gas temperture will drop slightly, and more gases will fall onto BH. On low net accretion rate, accretion flow’s temperature will be highly restrained, since more gases escaping.

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