文章基本信息

标题：Kinetic Tomography. II. A Second Method for Mapping the Velocity Field of the Milky Way Interstellar Medium and a Comparison with Spiral Structure Models
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作者：Kirill Tchernyshyov ; J. E. G. Peek ; Gail Zasowski 等
期刊名称：The Astronomical journal
印刷版ISSN：0004-6256
电子版ISSN：1538-3881
出版年度：2018
卷号：156
期号：6
页码：1-18
DOI：10.3847/1538-3881/aae68d
语种：English
出版社：American Institute of Physics
摘要：In this work, we derive a spatially resolved map of the line-of-sight velocity of the interstellar medium and use it, along with a second map of line-of-sight velocity from Paper I of this series, to determine the nature of the gaseous spiral structure in the Milky Way (MW). This map is derived from measurements of the 1.527μm diffuse interstellar band (DIB) in stellar spectra from the Apache Point Observatory Galactic Evolution Experiment survey and covers the nearest 4–5kpc of the Northern Galactic plane. We cross-check this new DIB-based line-of-sight velocity map with the map derived in Paper I and find that they agree. We then compare these maps with line-of-sight velocity maps derived from simulations of quasi-stationary density wave spiral structure and dynamic, or material, spiral structure in a MW-like galaxy. While none of the maps derived from these simulations is an exact match to the measured velocity field of the MW, the measurements are more consistent with simulations of dynamic spiral structure. In the dynamic spiral structure simulation that best matches the measurements, the Perseus spiral arm is being disrupted.
关键词：galaxies: structure;ISM: kinematics and dynamics;methods: statistical