The spiral structure of the Milky Way  

作　　者：Ye Xu Li-Gang Hou Yuan-Wei Wu 

机构地区：[1]Purple Mountain Observatory, Chinese Academy of Sciences [2]CAS Key Laboratory of FAST, National Astronomical Observatories, Chinese Academy of Sciences [3]National Astronomical Observatories, Chinese Academy of Sciences [4]National Time Service Center, Key Laboratory of Precise Positioning and Timing Technology, Chinese Academy of Sciences

出　　处：《Research in Astronomy and Astrophysics》2018年第12期9-28,共20页天文和天体物理学研究（英文版）

基　　金：sponsored by the MOST (Grant No.2017YFA0402701);the NSFC (Grant Nos.11873019, 11673066 and 11503033);the CAS (Grant No.QYZDJ-SSW-SLH047);the Youth Innovation Promotion Association of CAS;supported by the Key Laboratory for Radio Astronomy, CAS;the Open Project Program of the Key Laboratory of FAST, NAOC, CAS;Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement

摘　　要：The morphology and kinematics of the spiral structure of the Milky Way are long-standing problems in astrophysics.In this review we firstly summarize various methods with different tracers used to solve this puzzle.The astrometry of Galactic sources is gradually alleviating this difficult situation caused mainly by large distance uncertainties, as we can currently obtain accurate parallaxes(a few μas) and proper motions(≈1 km s-1) by using Very Long Baseline Interferometry(VLBI).On the other hand, the Gaia mission is providing the largest, uniform sample of parallaxes for O-type stars in the entire Milky Way.Based upon the VLBI maser and Gaia O-star parallax measurements, nearby spiral structures of the Perseus, Local, Sagittarius and Scutum Arms are determined in unprecedented detail.Meanwhile, we estimate fundamental Galactic parameters of the distance to the Galactic center,R0, to be 8.35 ± 0.18 kpc, and circular rotation speed at the Sun, Θ0, to be 240±10 km s-1.We found kinematic differences between O stars and interstellar masers: the O stars, on average, rotate faster,>8 km s-1than maser-traced high-mass star forming regions.The morphology and kinematics of the spiral structure of the Milky Way are long-standing problems in astrophysics.In this review we firstly summarize various methods with different tracers used to solve this puzzle.The astrometry of Galactic sources is gradually alleviating this difficult situation caused mainly by large distance uncertainties, as we can currently obtain accurate parallaxes(a few μas) and proper motions(≈1 km s^(-1)) by using Very Long Baseline Interferometry(VLBI).On the other hand, the Gaia mission is providing the largest, uniform sample of parallaxes for O-type stars in the entire Milky Way.Based upon the VLBI maser and Gaia O-star parallax measurements, nearby spiral structures of the Perseus, Local, Sagittarius and Scutum Arms are determined in unprecedented detail.Meanwhile, we estimate fundamental Galactic parameters of the distance to the Galactic center,R_0, to be 8.35 ± 0.18 kpc, and circular rotation speed at the Sun, Θ_0, to be 240±10 km s^(-1).We found kinematic differences between O stars and interstellar masers: the O stars, on average, rotate faster,>8 km s^(-1) than maser-traced high-mass star forming regions.

关 键 词：Galaxy:structure Galaxy:kinematics and dynamics MASERS techniques:high angular resolution ASTROMETRY stars:formation 

分 类 号：P[天文地球]