Two-Temperature Coronal Flow above a Thin Disk
Two-Temperature Coronal Flow above a Thin Disk
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DOI：
10.1086/341138
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发表时间：
2002-04
期刊：
影响因子：
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通讯作者：
B. Liu;S. Mineshige;F. Meyer;E. Meyer-Hofmeister;T. Physics;K. Univ.;M. F. Astrophysik;
中科院分区：
文献类型：
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作者：
B. Liu;S. Mineshige;F. Meyer;E. Meyer-Hofmeister;T. Physics;K. Univ.;M. F. Astrophysik;
我们通过考虑离子和电子的温度差异以及康普顿冷却，将盘状日冕模型推广到星系核的内部区域。我们发现，质量蒸发率，因此在日冕中释放的吸积能量的分数，强烈地依赖于从磁盘的外缘，更大的速率导致更多的康普顿冷却，蒸发效率较低，和较弱的日冕传入的质量流的速率。我们还发现了对粘度的强烈依赖性，较高的粘度导致电晕中的质量流增强，因此从下面的圆盘中蒸发更多的气体。如果我们以爱丁顿速率为单位取吸积速率，我们的结果就变得与中心黑洞的质量无关了。该模型预测较弱的硬X射线的天体吸积率较高，如窄线塞弗特1星系的贡献，与观测结果一致。对于明亮的活动星系核，最内层日冕的强烈康普顿冷却是如此有效，以至于需要大量的额外加热来维持薄盘上方的日冕。
We extended the disk corona model to the inner region of galactic nuclei by including different temperatures in ions and electrons as well as Compton cooling. We found that the mass evaporation rate, and hence the fraction of accretion energy released in the corona, depend strongly on the rate of incoming mass flow from the outer edge of the disk, a larger rate leading to more Compton cooling, less efficient evaporation, and a weaker corona. We also found a strong dependence on the viscosity, with higher viscosity leading to an enhanced mass flow in the corona and therefore more evaporation of gas from the disk below. If we take accretion rates in units of the Eddington rate, our results become independent of the mass of the central black hole. The model predicts weaker contributions to the hard X-rays for objects with higher accretion rate like narrow-line Seyfert 1 galaxies, in agreement with observations. For luminous active galactic nuclei, strong Compton cooling in the innermost corona is so efficient that a large amount of additional heating is required to maintain the corona above the thin disk.