论文标题
气体吸收到星系和开尔文 - 霍尔姆尔兹的湍流
Gas accretion onto galaxies and Kelvin-Helmholtz turbulence
论文作者
论文摘要
在银河系的生命周期内，持续的星形形成表明，低金属气体从环境培养基中稳步流入。同样，大规模结构形成的宇宙学模拟意味着气体从内部的光环中积聚到星系中。直接观察很困难，但是近年来，获得了来自近代培养基的气体流入的观察指示。在这里，我们建议间接观察探针：寻找由积聚引起的大规模（超过KPC）的湍流。作为一个特定的例子，我们考虑了带有星系磁盘的积聚流共体，并认为将产生开尔文 - 赫尔莫茨的湍流。我们采用半分析模型的湍流模型，并得出了预期的湍流功率谱。后者证明具有独特的形状，可以与观察功率谱进行比较。作为一个说明性的例子，我们使用银河系的参数。
Continued star formation over the lifetime of a galaxy suggests that low metalicity gas is steadily flowing in from the circumgalactic medium. Also, cosmological simulations of large-scale structure formation imply that gas is accreted onto galaxies from the halo inside which they formed. Direct observations are difficult, but in recent years observational indications of gas inflows from a circumgalactic medium were obtained. Here we suggest an indirect observational probe: looking for large-scale (exceeding few kpc) turbulence caused by the accretion. As a specific example we consider an accretion flow coplanar with the galaxy disk, and argue that Kelvin-Helmholtz turbulence will be generated. We employ a semi-analytic model of turbulence and derive the expected turbulence power spectrum. The latter turns out to be of a distinctive shape that can be compared with observational power spectra. As an illustrative example we use parameters of the Milky Way galaxy.
