论文标题
关于银河系的分子气盘的比例高度
On the scale-height of the molecular gas disc in Milky Way-like galaxies
论文作者
论文摘要
我们研究了分子气盘的比例高度与分子星际介质的湍流速度分散在模拟中的银河系状星系中的湍流速度分散体之间的关系。我们发现，分子气体的垂直分布可以通过高斯函数描述，均匀尺度高约50 pc。我们研究了该尺度高度是否与重力和湍流之间的静水平衡状态一致。我们发现，使用总湍流速度分散体的静水预测（从KPC尺度观测中进行测量）给出了真实分子盘尺度高度的过度估计。使用离散巨型分子云（云云速度分散）的质心之间的静水预测导致更高的估计值。分子云内部内部的速度分散率通过局部增强的重力场提升。我们的结果表明，分子气体的观察需要达到单个分子云的尺度，以便准确确定分子盘尺度。
We study the relationship between the scale-height of the molecular gas disc and the turbulent velocity dispersion of the molecular interstellar medium within a simulation of a Milky Way-like galaxy in the moving-mesh code Arepo. We find that the vertical distribution of molecular gas can be described by a Gaussian function with a uniform scale-height of ~50 pc. We investigate whether this scale-height is consistent with a state of hydrostatic balance between gravity and turbulent pressure. We find that the hydrostatic prediction using the total turbulent velocity dispersion (as one would measure from kpc-scale observations) gives an over-estimate of the true molecular disc scale-height. The hydrostatic prediction using the velocity dispersion between the centroids of discrete giant molecular clouds (cloud-cloud velocity dispersion) leads to more-accurate estimates. The velocity dispersion internal to molecular clouds is elevated by the locally-enhanced gravitational field. Our results suggest that observations of molecular gas need to reach the scale of individual molecular clouds in order to accurately determine the molecular disc scale-height.
