甲醇脉泽搜寻及辐射性质研究

This project will use the international advanced radio telescopes (including Purple Mountain Observatory 13.7 m,German Bonn 100 m and Australia ATNF Mopra 22 m) to carry out single dish surveys for class I and class II methanol masers toward large samples of Bolocam survey in mm continuum emission in Galactic plane with the Caltech Submillimeter Observatory (BGPS) for the first time. And it will perform VLBI polarization observations for class II methanol masers toward EGOs with high resolution outflows identified from the Spitzer. Through these observations: 1) we will build up the largest and the most complete sample of class I methanol maser (It is expected to detect about one thousand class I methanol maser sources in this project); 2) statistical analysis in a large sample for the evolutionary relationship between the two type masers during the process of massive star formation; 3) explore the origin of the class II methanol maser, and massive star formation process and magnetic field effect on their formations. The project is closely linked to the hottest and forest research topics of methnaol maser (maser search and the origin of class II methanol maser) , and will create by far the largest class I methanol maser catalog. It will provide important observational evidences for the understanding of the formation of massive stars. Therefor the project has important research values and a large number of scientific outputs.

本项目利用国际上多架先进射电望远镜（包括国内紫金山天文台13.7米，德国Bonn 100米，澳大利亚ATNF Mopra 22米望远镜）首次对Caltech 望远镜Bolocam毫米波银道面巡天（BGPS）样本开展甲醇脉泽的单天线搜寻，并利用甚长基线干涉VLBI网（澳洲LBA及欧洲EVN VLBI网）对高分辨率外流源开展II型甲醇脉泽VLBI偏振观测研究。通过这些观测：1）建立迄今最大、最完备的I型甲醇脉泽源星表（预计可以探测到1000个脉泽源）；2）在大样本中统计分析I型与II型甲醇脉泽在大质量恒星形成过程中的演化关系；3）探索II型甲醇脉泽的起源问题及大质量恒星形成过程及磁场作用。该项目研究内容紧扣甲醇脉泽研究领域最热点、最前沿的问题-搜寻与起源的研究，将建立迄今最为完备的I型甲醇脉泽源星表，并为理解大质量恒星形成提供重要的观测证据。因此本研究项目具有重要的研究价值和可观的科学产出。

本项目主要对星际脉泽中最为重要的甲醇脉泽开展了系统的观测研究工作，利用国际先进射电望远镜开展了大样本的毫米波BGPS 源I 型与II 型甲醇脉泽的单天线搜寻工作，并利用甚长基线干涉VLBI 网开展II 型甲醇脉泽VLBI 的观测研究。顺利完成项目既定研究内容与目标。在项目执行期内，通过这些观测，取得了如下研究成果：1）完成BGPS源甲醇脉泽搜寻，并以此建立了迄今最大、最完备的I 型甲醇脉泽样本（包含了约500个I 型甲醇脉泽源）；2）探索了II 型甲醇脉泽的起源问题及大质量恒星形成过程及磁场作用；3）首次在河外星系中探测到I型甲醇超脉泽的辐射，并指出甲醇超脉泽可能区别于其它分子脉泽，成为研究河外星系恒星形成及星际介质反馈的重要工具。如上研究成果共计成文发表SCI论文15篇，完成项目考评指标。