STUDY OF 3D IMAGE OF PERSEUS-ARM-REGION IN THE GALAXY USING DIFFERENTIAL VLBI

（1）对水汽脉泽源W 49 N和OH43.8 -0的观测。1，进行了使用双波束VLBI系统命名为VERA（VLBI无线电天体测量勘探）。虽然两个源的剩余条纹相位由于大气波动而在360度上显示出快速变化，但是两个源之间的差分相位非常小，这表明通过双光束相位参考有效地去除了大气相位波动。(2)A利用线偏振VLBI观测资料，对英仙座臂W3 IRS 5恒星形成区的水汽脉泽云进行了磁场填图。用22.2GHz的VLBA探测到的61个水脉泽中，有16个是线偏振的，偏振度达13%。磁场矢量大致垂直于脉泽特征的空间排列。（3）利用水泽10米天线对Ori-KL区脉泽斑的光变曲线和偏振进行了监测观测。该天线具有22 GHz和43 GHz接收机，能够探测晚型星周围的水汽脉泽和SiO脉泽。该系统具有良好的线偏振测量性能。（4）利用日本的VLBI观测网（J-Net）对双星形成区W51 A的水汽脉泽进行了自行测量。对W51 A三个脉泽团中脉泽的三维运动学分析表明，它们之间的距离为6.1±1。3 kpc基于采用径向膨胀流的模型拟合方法。（5）观测了距银心15'以内的大振幅SiO脉泽源，共探测到79个，未探测到58个。（6）利用VERA水汽脉泽线对英仙座臂著名的大质量星星形成区W3 OH进行了差分VLBI观测，研究了它在英仙座臂的三维位置。

(1)The observations of a pair of water vapor maser sources, W49N and OH 43.8-0. 1, were carried out using the dual-beam VLBI system named VERA (VLBI Exploration of Radio Astrometry). While the residual fringe phases of both sources showed rapid variations over 360deg due to the atmospheric fluctuation, the differential phase between the two sources is very small, demonstrating that the atmospheric phase fluctuation was effectively removed by dual beam phase referencing.(2)A magnetic field mapping of water vapor maser clouds in the star-forming region W3 IRS5, which is in the Perseus Arm, has been made on the basis of the linear Polarization VLBI observation. Using the VLBA at 22.2GHz, 16 of 61 detected water masers were found to be linearly polarized with polarization degree up to 13%. The magnetic field vectors are roughly perpendicular to the spatial alignments of the maser features.(3)Mizusawa 10m antenna has performed monitoring observations of light curve and polarization of the maser spots around Ori-KL region. The antenna has 22GHz and 43GHz receivers, which are able to detect water vapor masers and SiO masers around late-type stars. The system has good performance for linear polarization measurement.(4)Proper-motion measurements of water vapor masers in the massive-star forming region W51A were carried out using Japanese VLBI network (J-Net). Analyses of the 3-D kinematics of the masers in three maser clusters of W51A indicates that the distance of it is 6.1±1. 3kpc based on a model-fitting method adopting a radially expanding flow.(5)SiO maser sources are surveyed towered large-amplitude variables within 15' of the Galactic center, resulting in 79 detections and 58 non-detections.(6)Monitoring differential VLBI has been performed toward one of the famous massive star forming region W3OH in the Perseus arm using VERA with water vapor maser line in order to study the 3-D position of it in the Perseus arm region.