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arXiv 0709.0523astro-ph
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管状星云中致密核心人口的性质：来自C18O观测的核心和云运动学

The nature of the dense core population in the pipe nebula: core and cloud kinematics from C18O observations

August A. Muench, Charles J. Lada, Jill M. Rathborne, João F. Alves, M. Lombardi

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Accepted to ApJ. 14 pages, 11 figures. Complete table at end of document
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摘要：

我们目前的分子线观测的94个黑暗的云核心确定的烟斗星云通过近红外消光映射。利用亚利桑那射电天文台12米望远镜，我们获得了这些核心在C_（18）O的J=1-0跃迁的光谱。我们使用测量的核心参数，即，天线温度，线宽，径向速度，半径和质量，探索这些核心的内部运动学以及它们通过较大分子云的径向运动。我们发现绝大多数暗消光核是真正的云核，而不是不相关的细丝的叠加。虽然我们确定没有显着的核心的内部气体运动和核心的其他物理参数之间的相关性，我们确定空间相关的径向速度的变化，概述了云的两个主要的运动学组成部分。最大的是一个15 pc长的灯丝，在空间维度和径向速度上都令人惊讶地狭窄。从管道的主干开始，这条灯丝显示出均匀的小C18 O线宽（dv~0.4kms-1），以及仅略高于气体声速的核心到核心的运动。第二个部分勾勒出一个大的（2 pc; 1000太阳质量）环状结构的一部分。与此组件相关联的核心显示比主云中更大的线宽和核心到核心运动。管道分子环可能代表了与这种云的形成有关的原始结构。

英文摘要：

We present molecular-line observations of 94 dark cloud cores identified in the Pipe nebula through near-IR extinction mapping. Using the Arizona Radio Observatory 12m telescope, we obtained spectra of these cores in the J=1-0 transition of C18O. We use the measured core parameters, i.e., antenna temperature, linewidth, radial velocity, radius and mass, to explore the internal kinematics of these cores as well as their radial motions through the larger molecular cloud. We find that the vast majority of the dark extinction cores are true cloud cores rather than the superposition of unrelated filaments. While we identify no significant correlations between the core's internal gas motions and the cores' other physical parameters, we identify spatially correlated radial velocity variations that outline two main kinematic components of the cloud. The largest is a 15pc long filament that is surprisingly narrow both in spatial dimensions and in radial velocity. Beginning in the Stem of the Pipe, this filament displays uniformly small C18O linewidths (dv~0.4kms-1) as well as core to core motions only slightly in excess of the gas sound speed. The second component outlines what appears to be part of a large (2pc; 1000 solar mass) ring-like structure. Cores associated with this component display both larger linewidths and core to core motions than in the main cloud. The Pipe Molecular Ring may represent a primordial structure related to the formation of this cloud.

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