TRIGONOMETRIC PARALLAXES OF HIGH MASS STAR FORMING REGIONS: THE STRUCTURE AND KINEMATICS OF THE MILKY WAY
TRIGONOMETRIC PARALLAXES OF HIGH MASS STAR FORMING REGIONS: THE STRUCTURE AND KINEMATICS OF THE MILKY WAY
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DOI：
10.1088/0004-637x/783/2/130
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发表时间：
2014-01
期刊：
影响因子：
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通讯作者：
M. Reid;K. Menten;A. Brunthaler;X. Zheng;T. Dame;Ye Xu;Yuanbin Wu;B. Zhang;A. Sanna
中科院分区：
文献类型：
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作者：
M. Reid;K. Menten;A. Brunthaler;X. Zheng;T. Dame;Ye Xu;Yuanbin Wu;B. Zhang;A. Sanna
欧洲VLBI网络和日本VLBI探索射电天体测量项目--棒和螺旋结构遗产调查--测量了100多个与年轻、大质量恒星有关的脉泽的三角视差和自行。这些测量为银河系中旋臂的存在提供了强有力的证据，精确地定位了许多旋臂节段，并产生了大约7°到20°的螺旋俯仰角。旋臂的宽度随着距离银河系中心的距离而增加。拟合轴对称的银河系模型，利用三维位置和速度信息，以及太阳和平均源特殊运动的保守先验，我们估计到银心的距离R0为8.34±0.16kpc，太阳的圆自转速度Θ为240±8 km S−1，以及在−5和16kpc的银心半径之间几乎平坦的自转曲线(斜率为0.2±0.4 km S−1kpc−1)。假设旋转曲线为“普适”旋涡星系形式，我们估计薄盘尺度长度为2.44±0.16kpc。对于如此庞大的数据集，参数R0和Θ0不再高度相关，并且对不同形式的旋转曲线相对不敏感。如果采用大质量恒星形成区在近圆形银河系轨道上的理论基础，我们估计出银河系自转方向的全球太阳运动分量V☉=14.6±5.0KM S−1。虽然Θ0和V☉显著相关，但这些参数的总和受到很好的约束，Θ0+V☉=255.2±5.1 KM S−1，以及太阳在其绕银心轨道上的角速度，(Θ0+V☉)/R0=30.5 7±0.43 km S−1kpc−1。这些参数提高了太阳和赫尔斯-泰勒双星脉冲星在银河系轨道上加速度的估计精度，大大降低了广义相对论预测引力辐射检验中的不确定性。
Over 100 trigonometric parallaxes and proper motions for masers associated with young, high-mass stars have been measured with the Bar and Spiral Structure Legacy Survey, a Very Long Baseline Array key science project, the European VLBI Network, and the Japanese VLBI Exploration of Radio Astrometry project. These measurements provide strong evidence for the existence of spiral arms in the Milky Way, accurately locating many arm segments and yielding spiral pitch angles ranging from about 7° to 20°. The widths of spiral arms increase with distance from the Galactic center. Fitting axially symmetric models of the Milky Way with the three-dimensional position and velocity information and conservative priors for the solar and average source peculiar motions, we estimate the distance to the Galactic center, R0, to be 8.34 ± 0.16 kpc, a circular rotation speed at the Sun, Θ0, to be 240 ± 8 km s−1, and a rotation curve that is nearly flat (i.e., a slope of −0.2 ± 0.4 km s−1 kpc−1) between Galactocentric radii of ≈5 and 16 kpc. Assuming a “universal” spiral galaxy form for the rotation curve, we estimate the thin disk scale length to be 2.44 ± 0.16 kpc. With this large data set, the parameters R0 and Θ0 are no longer highly correlated and are relatively insensitive to different forms of the rotation curve. If one adopts a theoretically motivated prior that high-mass star forming regions are in nearly circular Galactic orbits, we estimate a global solar motion component in the direction of Galactic rotation, V☉ = 14.6 ± 5.0 km s−1. While Θ0 and V☉ are significantly correlated, the sum of these parameters is well constrained, Θ0 + V☉ = 255.2 ± 5.1 km s−1, as is the angular speed of the Sun in its orbit about the Galactic center, (Θ0 + V☉)/R0 = 30.57 ± 0.43 km s−1 kpc−1. These parameters improve the accuracy of estimates of the accelerations of the Sun and the Hulse–Taylor binary pulsar in their Galactic orbits, significantly reducing the uncertainty in tests of gravitational radiation predicted by general relativity.