Modelling the structure of molecular clouds – I. A multiscale energy equipartition
Modelling the structure of molecular clouds – I. A multiscale energy equipartition
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DOI：
10.1093/mnras/stw781
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发表时间：
2016-03
影响因子：
4.8
通讯作者：
T. Veltchev;S. Donkov;R. Klessen
中科院分区：
文献类型：
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作者：
T. Veltchev;S. Donkov;R. Klessen
我们提出了一个模型来描述分子云（MC）在早期演化阶段的质量-尺寸关系的一般结构。大小是通过阈值水平来定义的，在阈值水平上，重力能、湍流能和热能被均分。|W|\sim f（E_{\rmkin} + E_{\rmth}）$的发生，采用相互依赖的速度弥散和密度的标度关系，并假设在每个尺度上的对数正态密度分布。均分系数的变化允许在典型MCs的大小范围内（$\gtrsim$4 pc）的尺度上对恒星形成区域进行建模。最佳拟合获得低或没有星星形成的地区（管，北极星），以及为这样的恒星形成活动，但与近对数正态分布的柱密度（玫瑰）。该模型的一个额外的数值试验表明，它的适用性云的演化时间之前形成的第一颗恒星。
We present a model for describing the general structure of molecular clouds (MCs) at early evolutionary stages in terms of their mass-size relationship. Sizes are defined through threshold levels at which equipartitions between gravitational, turbulent and thermal energy $|W| \sim f(E_{\rm kin} + E_{\rm th})$ take place, adopting interdependent scaling relations of velocity dispersion and density and assuming a lognormal density distribution at each scale. Variations of the equipartition coefficient $1\le f\le 4$ allow for modelling of star-forming regions at scales within the size range of typical MCs ($\gtrsim$4 pc). Best fits are obtained for regions with low or no star formation (Pipe, Polaris) as well for such with star-forming activity but with nearly lognormal distribution of column density (Rosette). An additional numerical test of the model suggests its applicability to cloud evolutionary times prior to the formation of first stars.