Proper Motion of the Andromeda Galaxy: The Key to Local Group Masses and Dynamics

这个为期三年的项目提供了仙女座星系（M31）中水脉波的天体测量，这是银河系在本星系群中的大型伴星螺旋星系。大麦哲伦星云和小麦哲伦星云（LMC和SMC）和M33的正常运动已经有了或多或少足够的精度，但M31及其许多矮伴星和恒星流的正常运动是这个谜题中缺失的一块。对M31进行适当的运动测量对于更好地了解暗物质分布和本星系群的运动学是必要的。这些测量结果有望对星系研究产生更大的影响，因为它们限制了本星系群的形成和历史模型，以及未来的演化。观测使用了超长基线阵列、扩展甚大阵列和高灵敏度阵列的新功能。这项工作的更广泛的影响还包括培训新的观察员使用nsf支持的设施。PI将他的研究成果整合到课堂上，并致力于开发旨在改变各级教学天文学课程的工具和技术。该项目将把三门课程从传统的授课转变为提问-讨论-辅导。

This three-year project provides astrometry of water masers in the Andromeda Galaxy (M31), the large companion spiral galaxy to the Milky Way in the Local Group of galaxies. The proper motion of the Large and Small Magellanic Clouds (LMC, and SMC) and M33 are already known with more or less adequate accuracy, but the proper motion of M31 and its many dwarf companions and stellar streams is the missing piece in the puzzle. The proper motion measurement of M31 is necessary to get a better understanding of the dark matter distribution and kinematics of the Local Group. The measurements can be expected to have a larger impact on galactic research because they constrain models of the formation and history, but also future evolution, of the Local Group of galaxies. The observations use new capabilities of the Very Long Baseline Array, Expanded Very Large Array, and High Sensitivity Array. The broader impacts of this work further include training new observers to use NSF-supported facilities. The PI integrates results from his research into the classroom and works on tools and techniques aimed to transform astronomy courses at all levels of instruction. This program will transform three courses spanning the range of instruction level from traditional lectures into question-discussion-tutorial sessions.