黑洞周围热吸积流中冷团块的数值模拟
Numerical simulations of cold clumps in the hot accretion flows around black holes
AI总结：
本文通过数值模拟研究了黑洞周围热吸积流中冷团块的形成与演化，发现团块初始向外移动并最终碎裂向内移动，结果与半解析模型一致。
摘要：
先前的数值模拟显示，在热吸积流中可以形成冷团块，为黑洞X射线双星中状态转变的详细过程提供了见解。然而，冷团块的演变尚未被详细研究。在本文中，我们进行了水动力学模拟以研究冷团块的演变。除了之前的结果，即当吸积率足够高时，冷团块会在热吸积流中出现外，我们发现团块在最初形成时并非直接向黑洞移动，而是向外移动。原因应是粘性扭矩和从较大半径处冷凝的热气体的结合，导致团块具有略高于开普勒的角动量。当达到平衡位置后，团块在内边缘开始碎裂，每个碎片依次向内移动。一般来说，团块的方位运动是准开普勒式的，更接近于外侧脱离的冷盘而不是周围的亚开普勒热吸积流，这与Wang等人(2012)在弱耦合情况下的半解析结果相符。
英文摘要：
Previous numerical simulations have shown that cold clumps can form within hot accretion flows, offering insights into the detailed processes of the state transition in black hole X-ray binaries. However, the evolution of the cold clumps has not been investigated in detail yet. In this paper, we conduct hydrodynamic simulations to investigate the evolution of the cold clumps. In addition to previous result that when the accretion rate is high enough the cold clumps emerge within the hot accretion flow, we found that instead of directly moving toward to the black hole, the clumps moves outward when they initially form. The reason should be the combination of viscous torque and the condensation of hot gas from larger radii, which lead to the slightly super-Keplerian angular momentum of the clumps. After reaching the equilibrium position, the clumps begin to fragment at the inner edge with each fragment moving inward sequentially. Generally, the azimuthal movement of the clumps are quasi-Keplerian, being closer to the outer detached Keplerian cold disk rather than the surrounding sub-Keplerian hot accretion flow, which agrees well with the semi-analytical results for weak coupling case in Wang et al. (2012).
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
