Star Formation in Turbulent Molecular Clouds with Colliding Flow
Star Formation in Turbulent Molecular Clouds with Colliding Flow
复制标题
碰撞流湍流分子云中的恒星形成
DOI：
10.1088/0004-637x/801/2/77
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
T. Shimoikura
中科院分区：
文献类型：
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作者：
T. Matsumoto;K. Dobashi;T. Shimoikura
利用自引力流体动力学数值模拟方法，研究了高密度湍流分子云在碰撞流作用下的演化过程。湍流引起的激波相互作用产生了宽度小于秒差距的薄对流云网络。碰撞流将对流云聚集成片状云，并促进最初高密度云的活跃星星形成。有碰撞流的云比没有碰撞流的云表现出更精细的对流网络。对于无碰撞流的云，密度和柱密度的概率分布函数（PDF）可以用对数正态函数拟合。当初始湍流较弱时，柱密度PDF在高柱密度时具有幂律翼。碰撞流使PDF显著变形，使得PDF呈现双峰。当初始云密度较高时，这里再现的恒星质量分布与经典初始质量函数一致，幂律指数为-1.35。恒星速度的分布与气体速度的分布一致，对于没有碰撞流的云，气体速度的分布可以用高斯函数拟合。对于具有碰撞流的云，气体的速度色散往往大于恒星的速度色散。碰撞流和湍流的特征出现在从模拟数据重建的通道图中。没有碰撞流的云由于湍流而表现出云尺度的速度切变。与此相反，云与碰撞流显示出显着的反相关分布的薄丝之间的不同的速度通道，这表明碰撞云之间的碰撞。
Using self-gravitational hydrodynamical numerical simulations, we investigated the evolution of high-density turbulent molecular clouds swept by a colliding flow. The interaction of shock waves due to turbulence produces networks of thin filamentary clouds with a sub-parsec width. The colliding flow accumulates the filamentary clouds into a sheet cloud and promotes active star formation for initially high-density clouds. Clouds with a colliding flow exhibit a finer filamentary network than clouds without a colliding flow. The probability distribution functions (PDFs) for the density and column density can be fitted by lognormal functions for clouds without colliding flow. When the initial turbulence is weak, the column density PDF has a power-law wing at high column densities. The colliding flow considerably deforms the PDF, such that the PDF exhibits a double peak. The stellar mass distributions reproduced here are consistent with the classical initial mass function with a power-law index of− 1.35 when the initial clouds have a high density. The distribution of stellar velocities agrees with the gas velocity distribution, which can be fitted by Gaussian functions for clouds without colliding flow. For clouds with colliding flow, the velocity dispersion of gas tends to be larger than the stellar velocity dispersion. The signatures of colliding flows and turbulence appear in channel maps reconstructed from the simulation data. Clouds without colliding flow exhibit a cloud-scale velocity shear due to the turbulence. In contrast, clouds with colliding flow show a prominent anti-correlated distribution of thin filaments between the different velocity channels, suggesting collisions between the filamentary clouds.