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arXiv 1902.00360astro-ph.HEhep-th
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大质量黑洞的辐射非等温Bondi吸积

Radiative non-isothermal Bondi accretion onto a massive black hole

J. M. Ramirez-Velasquez, L. Di G. Sigalotti, R. Gabbasov, F. Cruz, J. Klapp, Ernesto Contreras

摘要:

本文给出了超大质量黑洞非等温吸积过程的经典Bondi吸积理论,包括X射线加热、电子散射辐射力和谱线的影响.辐射场的计算考虑了光学厚,几何薄,标准的吸积盘作为紫外光子的发射器和作为X射线发射源的球形中心对象。在目前的分析中,紫外线发射的吸积盘被假定为有一个角度的依赖性,而X射线/中心对象的辐射被假定为各向同性。这使我们能够在任何需要的角度方向上建立流线。这两种类型的辐射的影响进行了评估,为不同的通量分数的X射线和紫外线的排放,并没有谱线驱动的影响。我们发现在SMBH附近发射的辐射与下落的物质相互作用,并修改吸积动力学。在存在直线驱动的情况下,类似于从纯1型和2型到5型解的过渡(见Frank等人的图2.1)。2002),其发生而不管UV发射是否超过X射线发射。我们计算这种转变发生时的辐射因子,并从我们所有的模型中丢弃类型5的解决方案。给出了吸积半径和吸积率的经典Bondi值估计值。这一结果对于构造星系中心SMBH吸积流的含时流体动力学模拟的初始条件是有用的。

英文摘要:

In this paper, we present the classical Bondi accretion theory for the case of non-isothermal accretion processes onto a supermassive black hole (SMBH), including the effects of X-ray heating and the radiation force due to electron scattering and spectral lines. The radiation field is calculated by considering an optically thick, geometrically thin, standard accretion disk as the emitter of UV photons and a spherical central object as a source of X-ray emission. In the present analysis, the UV emission from the accretion disk is assumed to have an angular dependence, while the X-ray/central object radiation is assumed to be isotropic. This allows us to build streamlines in any angular direction we need to. The influence of both types of radiation is evaluated for different flux fractions of the X-ray and UV emissions with and without the effects of spectral line driving. We find that the radiation emitted near the SMBH interacts with the infalling matter and modifies the accretion dynamics. In the presence of line driving, a transition resembles from pure type 1 & 2 to type 5 solutions (see Fig2.1 of Frank etal. 2002), which takes place regardless of whether or not the UV emission dominates over the X-ray emission. We compute the radiative factors at which this transition occurs, and discard type 5 solution from all our models. Estimated values of the accretion radius and accretion rate in terms of the classical Bondi values are also given. The results are useful for the construction of proper initial conditions for time-dependent hydrodynamical simulations of accretion flows onto SMBH at the centre of galaxies.

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