Classification of Filament Formation Mechanisms in Magnetized Molecular Clouds
Classification of Filament Formation Mechanisms in Magnetized Molecular Clouds
复制标题
磁化分子云中细丝形成机制的分类
DOI：
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Tomoaki Matsumoto
中科院分区：
文献类型：
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作者：
D. Abe;T. Inoue;S. Inutsuka;Tomoaki Matsumoto
最近对分子云的观察表明，致密的细丝是当今恒星形成的场所。因此，有必要了解灯丝的形成过程，因为这些灯丝为恒星的形成提供了初始条件。理论研究表明，分子云中的激波触发了细丝的形成。由于已经提出了几种不同的细丝形成机制，因此观测到的恒星形成细丝的形成机制需要澄清。在本研究中，我们对细丝的形成进行了一系列等温磁流体动力学模拟。我们重点研究了激波速度和湍流对细丝形成机制的影响，并确定了三种不同的细丝形成机制。结果表明：当激波速度为v sh≃7 km s−1时，在弯曲激波的驱动下，无论是否存在湍流和自重力，气体都能形成细丝；当慢激波速度v sh≃2.5 km s−1时，参与初始湍流的压缩流分量诱导了纤维的形成。当激波速度和湍流度都较低时，激波压缩片材的自重力对细丝的形成至关重要。此外，我们分析了丝的线质量分布，表明强激波可以在短时间内自然地产生高线质量丝，例如在大质量恒星形成区域中观察到的丝。我们得出结论，主导的细丝形成模式随着触发细丝形成的激波速度的变化而变化。
Recent observations of molecular clouds show that dense filaments are the sites of present-day star formation. Thus, it is necessary to understand the filament formation process because these filaments provide the initial condition for star formation. Theoretical research suggests that shock waves in molecular clouds trigger filament formation. Since several different mechanisms have been proposed for filament formation, the formation mechanism of the observed star-forming filaments requires clarification. In the present study, we perform a series of isothermal magnetohydrodynamics simulations of filament formation. We focus on the influences of shock velocity and turbulence on the formation mechanism and identified three different mechanisms for the filament formation. The results indicate that when the shock is fast, at shock velocity v sh ≃ 7 km s−1, the gas flows driven by the curved shock wave create filaments irrespective of the presence of turbulence and self-gravity. However, at a slow shock velocity v sh ≃ 2.5 km s−1, the compressive flow component involved in the initial turbulence induces filament formation. When both the shock velocities and turbulence are low, the self-gravity in the shock-compressed sheet becomes important for filament formation. Moreover, we analyzed the line-mass distribution of the filaments and showed that strong shock waves can naturally create high-line-mass filaments such as those observed in the massive star-forming regions in a short time. We conclude that the dominant filament formation mode changes with the velocity of the shock wave triggering the filament formation.
冲击流形成自重力细丝：细丝上的速度梯度
影响因子：
4.8
作者：
Chen, Che-Yu;Mundy, Lee G;Ostriker, Eve C;Storm, Shaye;Dhabal, Arnab
通讯作者：
Dhabal, Arnab