The Universality of Turbulence in Galactic Molecular Clouds
The Universality of Turbulence in Galactic Molecular Clouds
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DOI：
10.1086/425978
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发表时间：
2004-09
期刊：
影响因子：
--
通讯作者：
M. Heyer;C. Brunt
中科院分区：
文献类型：
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作者：
M. Heyer;C. Brunt
通过对27个巨分子云结构函数的观测和Monte Carlo模拟，考察了星际湍流的普遍性。我们发现，结构函数，δv = volγ，来自宽场成像的12 CO J=1-0发射从个别云描述的一个狭窄的范围内的标度指数，γ，和标度系数，vo。湍流结构函数的相似性强调了分子星际介质中湍流的普遍性，并解释了拉尔森最初确定的云与云的尺寸/线宽关系。湍流普遍性的程度是量化的蒙特卡罗模拟再现所观察到的云到云的关系的均方速度残差。分子云的标度振幅和标度指数变化的上限约为10%-20%。测量的湍流的不变性的分子云有很大的不同的大小，环境，和星星形成的活动，建议一个共同的形成机制，如收敛湍流内的扩散星际介质和有限的贡献，从云内的大规模驱动机制的能源。
The universality of interstellar turbulence is examined from observed structure functions of 27 giant molecular clouds and Monte Carlo modeling. We show that the structure functions, δv = volγ, derived from wide-field imaging of 12CO J=1-0 emission from individual clouds are described by a narrow range in the scaling exponent, γ, and the scaling coefficient, vo. The similarity of turbulent structure functions emphasizes the universality of turbulence in the molecular interstellar medium and accounts for the cloud-to-cloud size/line width relationship initially identified by Larson. The degree of turbulence universality is quantified by Monte Carlo simulations that reproduce the mean squared velocity residuals of the observed cloud-to-cloud relationship. Upper limits to the variation of the scaling amplitudes and exponents for molecular clouds are ~10%-20%. The measured invariance of turbulence for molecular clouds with vastly different sizes, environments, and star formation activity suggests a common formation mechanism such as converging turbulent flows within the diffuse interstellar medium and a limited contribution of energy from sources within the cloud with respect to large-scale driving mechanisms.