Observational Study of the Physical Properties of the Hierarchy Commonly Found in Star-Forming Molecular Clouds

我们对三个典型的恒星形成云(金牛座、猎户座和蛇夫座)进行了高质量的测绘观测，以研究分子云中的等级结构及其对恒星形成的影响。配备了25波束阵列接收器系统(BEAS)的Nobeama 45米望远镜使其能够均匀地覆盖从云的整体延伸(-1 pC)到可与云核相媲美的小尺度(-0.01 pC)的空间范围。主要研究结果如下：1.本文的主要研究成果如下。开发了一个新的熊观测数据分析系统(BMAS)。我们利用BEARS开发了一个新的大比例尺高分辨率测绘数据分析系统(BMAS)。在工作站平台上使用IDL编程语言，BMAS具有用户友好的图形用户界面。射电天文学的标准分析工具和包括频谱分析在内的统计分析工具都是在BMAS中构建的。使用BMAS可以高效地分析熊的海量数据。分子云中比核心更小的团块的优势。通过分析BMAS的高质量测图数据，我们发现分子云中比核心更小的精细结构(团块)占主导地位。团团被认为在云核内的恒星形成中起着重要作用。此外，我们还发现了以下针对单个星云的新结果：在金牛座星云中，我们提出了一种新的基于稠密气体空间分布的原恒星分类方法。在猎户座星云中，众所周知的大尺度丝状结构中存在着细丝。在蛇夫座星云中，我们通过将我们的测绘数据与ISO拍摄的红外图像进行比较，揭示了恒星形成核心的早期演化。我们的分析正在进行中。

We have made high-quality mapping observations toward the three typical star-forming clouds (Taurus, Orion, and Ophiuchus), in order to investigate the hierachical structure in molecular clouds and its influence on star formation. The Nobeyama 45 m telescope equipped with the 25-beam array receiver system (BEARS) makes it possible to homogeneously cover the spatial ranges from the overall extension (-1 pc) of the clouds down to small scales (-0.01 pc) comparable to cloud cores. Our main results are as follows.1. Development of a new data analysis system (BMAS) for BEARS observations.We have developped a new analysis system (BMAS) for large-scale and high-resolution mapping data with BEARS.We used the programming language, IDL on workstation platforms and BMAS has GUI which is user-friendly. Standard analysis tools in radio astronomy and statistical analysis tools including spectral analysis are built in BMAS.One can efficiently analyze huge data from BEARS with BMAS.2. Dominance of smaller clumps than cores in molecular clouds.We have found that fine structures (clumps) smaller than cores are dominant in molecular clouds by analyzing the BEARS high-quality mapping data with BMAS.The clumps are considered to play an important role in star formation within cloud cores. Furthermore, we found the following new results for individual clouds, In the Taurus cloud, we propose a new classification of protostars based on the spatial distribution of dense gas. In the Orion cloud, there exist fine filaments in the well-known large-scale filamentary structure. And in the Ophiuchus cloud, we revealed the early evolution of star-forming cores by comparing our mapping data with the infrared images taken by ISO.Our analysis is in progress.