标题： 分子间介质分形结构的自引力解释 显示英文标题

标题： Self-gravity as an explanation of the fractal structure of the interstellar medium

摘要： 星系际介质的气体云具有分形结构，其起源一般被认为是湍流造成的。 湍流的能量可能来自大尺度上的银河系旋转，然后通过耗散作用向下传递到小尺度上；有人提出这种湍流有助于防止大质量分子云因自身引力而坍缩。 在这里我们表明，相反，自引力本身可能是使云层呈现分形结构的主要因素。 我们发展了一种场论方法来研究云层的结构，假设它们是等温的，并且只有引力相互作用；我们发现，从这种方法自然会产生出云层的观测分形维数。 虽然这个结果并不意味着湍流不重要，但它确实证明了分形结构可以在没有湍流的情况下被理解。 显示英文摘要

摘要： The gas clouds of the interstellar medium have a fractal structure, the origin of which has generally been thought to lie in turbulence. The energy of turbulence could come from galactic rotation at large-scale, then cascade down to be dissipated on small-scales by viscosity; it has been suggested that such turbulence helps to prevent massive molecular clouds from collapsing in response to their own gravity. Here we show that, on the contrary, self-gravity itself may be the dominant factor in making clouds fractal. We develop a field-theory approach to the structure of clouds, assuming them to be isothermal, and with only gravitational interactions; we find that the observed fractal dimension of the clouds arise naturally from this approach. Although this result does not imply that turbulence is not important, it does demonstrate that the fractal structure can be understood without it.