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arXiv 1306.1090astro-ph.GAastro-ph.CO
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盘风的维里化：对AGN黑洞质量估计的意义

On the Virialization of Disk Winds: Implications for the Black Hole Mass Estimates in AGN

Amit Kashi, Daniel Proga, Kentaro Nagamine, Jenny Greene, Aaron J. Barth

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Accepted to ApJ
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摘要：

估算活动星系核中超大质量黑洞的质量通常依赖于宽线区维里化的假设。然而，这种假设似乎是无效的BLR模型，包括一个吸积盘和它的风。圆盘可能是开普勒的，因此维里化了。然而，风的物质，超过一定的点，必须由一个向外的力量，比重力更强。在这里，我们分析了四种不同的磁盘风的流体动力学模拟：等温风，热风从X射线加热磁盘，和两个线驱动的风，一个和其他没有X射线加热和冷却。对于每一个模型，我们检查重力是否支配的流动特性，通过计算和分析的体积积分量，出现在维里定理：内部，动能和引力能，我们发现，在前两个模型中，风是非维里化，而两个线驱动盘风维里化到一个相对较大的距离。线驱动风是维里化的，因为它们加速缓慢，旋转速度占主导地位，风基非常密集。对于两种维里化风，所谓的投影维里因子与倾角成比例，为$1/ \sin^2{i}$。最后，我们证明，从开普勒磁盘流出变得unvirialized更慢，当它保存的气体比角动量-在这里考虑的模型，比当它保存的角速度-在所谓的磁离心风。

英文摘要：

Estimating the mass of a supermassive black hole (SMBH) in an active galactic nucleus (AGN) usually relies on the assumption that the broad line region (BLR) is virialized. However, this assumption seems invalid in BLR models that consists of an accretion disk and its wind. The disk is likely Keplerian and therefore virialized. However, the wind material must, beyond a certain point, be dominated by an outward force that is stronger than gravity. Here, we analyze hydrodynamic simulations of four different disk winds: an isothermal wind, a thermal wind from an X-ray heated disk, and two line-driven winds, one with and the other without X-ray heating and cooling. For each model, we check whether gravity governs the flow properties, by computing and analyzing the volume-integrated quantities that appear in the virial theorem: internal, kinetic, and gravitational energies, We find that in the first two models, the winds are non-virialized whereas the two line-driven disk winds are virialized up to a relatively large distance. The line-driven winds are virialized because they accelerate slowly so that the rotational velocity is dominant and the wind base is very dense. For the two virialized winds, the so-called projected virial factor scales with inclination angle as $1/ \sin^2{i}$. Finally, we demonstrate that an outflow from a Keplerian disk becomes unvirialized more slowly when it conserves the gas specific angular momentum -- as in the models considered here, than when it conserves the angular velocity -- as in the so-called magneto-centrifugal winds.

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