TRIGONOMETRIC PARALLAXES OF MASSIVE STAR-FORMING REGIONS. VI. GALACTIC STRUCTURE, FUNDAMENTAL PARAMETERS, AND NONCIRCULAR MOTIONS

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	TRIGONOMETRIC PARALLAXES OF MASSIVE STAR-FORMING REGIONS. VI. GALACTIC STRUCTURE, FUNDAMENTAL PARAMETERS, AND NONCIRCULAR MOTIONS
	Reid, M. J.1; Menten, K. M.2; Zheng, X. W.3; Brunthaler, A.2; Moscadelli, L.4; Xu, Y.2,5 ; Zhang, B.3; Sato, M.1,6; Honma, M.6; Hirota, T.6
刊名	ASTROPHYSICAL JOURNAL
	2009-07-20
卷号	700 期号:1 页码:137-148
关键词	astrometry Galaxy: fundamental parameters Galaxy: halo Galaxy: kinematics and dynamics Galaxy: structure stars: formation
ISSN号	0004-637X
英文摘要	We are using the Very Long Baseline Array and the Japanese VLBI Exploration of Radio Astronomy project to measure trigonometric parallaxes and proper motions of masers found in high-mass star-forming regions across the Milky Way. Early results from 18 sources locate several spiral arms. The Perseus spiral arm has a pitch angle of 16 degrees +/- 3 degrees, which favors four rather than two spiral arms for the Galaxy. Combining positions, distances, proper motions, and radial velocities yields complete three-dimensional kinematic information. We find that star-forming regions on average are orbiting the Galaxy approximate to 15 km s(-1) slower than expected for circular orbits. By fitting the measurements to a model of the Galaxy, we estimate the distance to the Galactic center R(0) = 8.4 +/- 0.6 kpc and a circular rotation speed Theta(0) = 254 +/- 16 km s(-1). The ratio Theta(0)/R(0) can be determined to higher accuracy than either parameter individually, and we find it to be 30.3 +/- 0.9 km s(-1) kpc(-1), in good agreement with the angular rotation rate determined from the proper motion of Sgr A*. The data favor a rotation curve for the Galaxy that is nearly flat or slightly rising with Galactocentric distance. Kinematic distances are generally too large, sometimes by factors greater than 2; they can be brought into better agreement with the trigonometric parallaxes by increasing Theta(0)/R(0) from the IAU recommended value of 25.9 km s(-1) kpc(-1) to a value near 30 km s(-1) kpc(-1). We offer a "revised" prescription for calculating kinematic distances and their uncertainties, as well as a new approach for defining Galactic coordinates. Finally, our estimates of Theta(0) and Theta(0)/R(0), when coupled with direct estimates of R(0), provide evidence that the rotation curve of the Milky Way is similar to that of the Andromeda galaxy, suggesting that the dark matter halos of these two dominant Local Group galaxy are comparably massive.
学科主题	Astronomy & Astrophysics
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	HIPPARCOS PROPER MOTIONS ; MILKY-WAY GALAXY ; ROTATION CURVE ; SPIRAL STRUCTURE ; BLACK-HOLE ; STELLAR ORBITS ; OB STARS ; DISTANCE ; DISK ; KINEMATICS
收录类别	SCI
语种	英语
WOS记录号	WOS:000267768900012
公开日期	2011-12-08
内容类型	期刊论文
源URL	[http://159.226.72.40/handle/332002/1657]
专题	紫金山天文台_紫金山天文台青海观测站
作者单位	1.Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA 2.Max Planck Inst Radioastron, D-53121 Bonn, Germany 3.Nanjing Univ, Dept Astron, Nanjing 210093, Peoples R China 4.Arcetri Observ, Florence, Italy 5.Chinese Acad Sci, Purple Mt Observ, Nanjing 210008, Peoples R China 6.Natl Astron Observ, VERA Project, Tokyo 1818588, Japan 7.Shanghai Astron Observ, Shanghai, Peoples R China 8.Natl Radio Astron Observ, Socorro, NM 87801 USA 9.Nicholas Copernicus Univ, Torun Ctr Astron, PL-87100 Torun, Poland
推荐引用方式 GB/T 7714	Reid, M. J.,Menten, K. M.,Zheng, X. W.,et al. TRIGONOMETRIC PARALLAXES OF MASSIVE STAR-FORMING REGIONS. VI. GALACTIC STRUCTURE, FUNDAMENTAL PARAMETERS, AND NONCIRCULAR MOTIONS[J]. ASTROPHYSICAL JOURNAL,2009,700(1):137-148.
APA	Reid, M. J..,Menten, K. M..,Zheng, X. W..,Brunthaler, A..,Moscadelli, L..,...&Bartkiewicz, A..(2009).TRIGONOMETRIC PARALLAXES OF MASSIVE STAR-FORMING REGIONS. VI. GALACTIC STRUCTURE, FUNDAMENTAL PARAMETERS, AND NONCIRCULAR MOTIONS.ASTROPHYSICAL JOURNAL,700(1),137-148.
MLA	Reid, M. J.,et al."TRIGONOMETRIC PARALLAXES OF MASSIVE STAR-FORMING REGIONS. VI. GALACTIC STRUCTURE, FUNDAMENTAL PARAMETERS, AND NONCIRCULAR MOTIONS".ASTROPHYSICAL JOURNAL 700.1(2009):137-148.