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arXiv 1807.08968astro-ph.GA
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分子细丝的形成和云的相互作用:来自Nobeyama 45 m望远镜观测的提示

Molecular filament formation and filament-cloud interaction: Hints from Nobeyama 45m telescope observations

Doris Arzoumanian, Yoshito Shimajiri, Shu-ichiro Inutsuka, Tsuyoshi Inoue, Kengo Tachihara

摘要:

我们提出Nobeyama 45米望远镜C18 O,13 CO和12 CO(1-0)映射观测到的金牛座分子云中的星际灯丝。我们研究了沿暗条及其周围母云中的气体速度结构。在光学薄的C18 O辐射中,暗条被探测到是一个单一的速度分量,长约1 pc,宽约0.06pc。C18 O的排放追踪到了密度大于~5x10^21 cm-2的尘柱。视线(LOS)速度沿灯丝波峰波动,平均振幅约为0.2 km/s。13 CO和12 CO积分强度图显示了细长细丝周围的空间扩展发射。我们确定了三个扩展结构的LOS速度红移和蓝移相对于平均速度的灯丝中确定的C18 O。结合分析速度积分通道图和强度变化的光学厚12 CO光谱上和关闭的灯丝,我们提出了一个三维结构的云周围的灯丝。我们进一步提出了一个多相互作用的情况下,片状的扩展结构相互作用,在空间和时间,与灯丝,并负责其压缩和/或中断,在恒星形成历史的灯丝发挥了重要作用。我们还发现,朝向同一个场,一个非常微弱的细丝显示出与Inoue等人提出的细丝形成过程兼容的速度场。(2017),其中细丝是由于星际冲击压缩引起的环境磁场结构弯曲产生的物质流的会聚而形成的。

英文摘要:

We present Nobeyama 45m telescope C18O, 13CO, and 12CO(1-0) mapping observations towards an interstellar filament in the Taurus molecular cloud. We investigate the gas velocity structure along the filament and in its surrounding parent cloud. The filament is detected in the optically thin C18O emission as a single velocity component, ~1pc long, ~0.06pc wide structure. The C18O emission traces dust column densities larger than ~5x10^21 cm-2. The line-of-sight (LOS) velocity fluctuates along the filament crest with an average amplitude of ~0.2 km/s. The 13CO and 12CO integrated intensity maps show spatially extended emission around the elongated filament. We identify three extended structures with LOS velocities redshifted and blueshifted with respect to the average velocity of the filament identified in C18O. Based on combined analyses of velocity integrated channel maps and intensity variations of the optically thick 12CO spectra on and off the filament, we propose a 3-dimensional structure of the cloud surrounding the filament. We further suggest a multi-interaction scenario where sheet-like extended structures interact, in space and time, with the filament and are responsible for its compression and/or disruption, playing an important role in the star formation history of the filament. We also identify, towards the same field, a very faint filament showing a velocity field compatible with the filament formation process proposed by Inoue et al. (2017), where a filament is formed due to convergence of a flow of matter generated by the bending of the ambient magnetic field structure induced by an interstellar shock compression.

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