Research on Galactic dynamics with maser sources

这项研究的目的是通过测量微波激射源的径向速度来研究银河系的旋转曲线，这种测量具有射电天文学技术现在可以获得的高精度。高灵敏度的射电观测将位置天文学的方法扩展到整个银河系，而位置天文学是基于对附近恒星的观测。我们还测量了SiO和OH/H_2O脉泽的径向速度，得到了银河系的自转曲线，阐明了气体和恒星运动的差异。我们还测试了测量附近脉泽源自行的可能性。利用JHK红外成像观测资料对脉泽源进行了识别：在角秒精度下测量了恒星的位置，并从近、中红外光谱能量分布中确定了距离，通过对这些射电和近红外观测资料的分析，得到了初步的结果;（1）银河系外SiO脉泽源的径向速度数据表明，在太阳附近，银河系自转曲线随半径缓慢减小，富氧星和富碳星在近红外色指数上具有不同的特征。(2)在Sgr B分子云方向上发现了大量SiO脉泽源，并在近红外成像上被确认为恒星。我们还发现了许多SiO脉泽源在1角分钟内从银河系中心。(3)本文分析了水脉泽斑的位置和速度数据，揭示了水脉泽斑的加速运动，在此基础上，证实了用射电和红外技术相结合的方法高精度测量银河系中恒星运动的可能性。

The purpose of this research was to investigate the rotation curve of the Galaxt by measuring the radial velocities of maser sources with high accuracy that is now available with techniques in radio astronomy. The high sensitivity radio observations extends the method of positional astronomy, which were based on the observations on nearby stars, to all the way in the Galaxy. We have measured radial velocities of SiO and OH/H2O masers ources, obtained the rotation curve of the Galaxy, and clarify the difference of motion between the gas and stars. We also tested a possibility of measuring proper motions of nearby maser sources. we have identified the maser sources with infrared JHK imaging observations : positions of stars were measured in an accuracy of arcsec, and determined the distances from the spectral energy distribution in the near and mid infrared data.With the analyzes of the data obtained by these radio and near-infrared observations, we have obtained the foolowing results ;(1) The radial velocity data of SiO maser sources at the outer Galaxy show that the Galactic rotation curve is slowly decreasing with radius near the solar neibourhood, and the oxygen-and carbon-rich stars have a different characteristic in the near-infrared color index.(2) We founda number of SiO maser sources in the directions of Sgr B molecular cloud and they are identified at the near-infrared imaging as stars. We also found many SiO maser sources within 1 arc minute from the Galactic center.(3) Analyzes the positional and velocity data of water maser spots revealed the presence of accelerating motion of the maser spots.Based on these observations, we have confirmed the possibility of measuring stellar motions in the Galaxy with high accuracy by the method combining the radio and infrared techniques.