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

我们对三种典型的恒星形成云（金牛座、猎户座和蛇夫座）进行了高质量的测绘观测，以研究分子云的层次结构及其对恒星形成的影响。Nobeyama 45米望远镜配备了25束阵列接收系统（BEARS），可以均匀地覆盖从云的整体延伸（-1个百分点）到小尺度（-0.01个百分点）的空间范围，与云核相当。我们的主要结果如下：开发新的bear观测数据分析系统（BMAS）。我们开发了一个新的分析系统（BMAS），用于大尺度和高分辨率的地图数据。我们在工作站平台上使用了编程语言IDL， BMAS具有用户友好的GUI。在BMAS中建立了射电天文学的标准分析工具和包括光谱分析在内的统计分析工具。使用BMAS.2可以有效地分析来自BEARS的海量数据。在分子云中，小团块比核块占优势。通过对bear高质量测绘数据的分析，我们发现分子云中比核心小的精细结构（团块）占主导地位。团块被认为在云核内的恒星形成中起着重要作用。在金牛座星云中，我们根据致密气体的空间分布提出了一种新的原恒星分类方法。在猎户座星云中，存在着众所周知的大规模细丝结构中的细丝。在蛇夫座云中，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.