薄分子云湍流结构函数的倾角改正及其应用  

The Inclination Correction to the Turbulence Structure Function of Thin Molecular Clouds and Its Application

作　　者：钱磊[1,2] QIAN Lei(National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101;School of Astronomy and Space Science,University of Chinese Academy of Sciences,Beijing 100049)

机构地区：[1]中国科学院国家天文台,北京100101 [2]中国科学院大学天文与空间科学学院,北京100049

出　　处：《天文学报》2021年第1期82-87,共6页Acta Astronomica Sinica

基　　金：国家重点研发项目(2017YFA0402600);中国科学院青年创新促进会(会员编号:2018075);国家自然科学基金项目(U1631237)资助。

摘　　要：通过结构函数可以测量湍流的能量级联速率.在实际观测中,无法测量分子云中气体的3维速度,这使得其湍流结构函数难以测量.对垂直于视线方向的薄分子云的情形,结构函数Stt2可以通过云核速度弥散(core velocity dispersion,CVD)进行测量,CVD2=1/2Stt2.对此进行推广,对于不垂直于视线方向的薄分子云,CVD2=1/2Stt2(1-1/8cos2θ)R2/3,其中,θ是视线方向与投影方向的夹角,平均投影距离与3维距离之比R可以用第2类椭圆积分E(k,φ)表示为R=2/πE(cosθ,π/2).The energy cascade rate of turbulence can be measured with the structure function.In practice,the 3D velocity of the gas in molecular cloud is hard to measure,which makes the measurement of structure function difficult.In the case of thin molecular clouds perpendicular to the line of sight,the structure function Stt2 can be measured with core velocity dispersion(CVD),CVD2=1/2Stt2.This method was extended to the case when the thin molecular cloud is not perpendicular to the line of sight,with intersection angleθ,CVD2=1/2Stt2(1-1/8cos2θ)R2/3,where R is the ratio of the average projected distance to the 3D distance,can be expressed with elliptic integrals of the second kind E(k,φ)as R=2/πE(cosθ,π/2).

关 键 词：星际介质:分子云 星际介质:运动学和动力学 星际介质:谱线 

分 类 号：P141[天文地球—天体物理]