Trigonometric Parallaxes of High-mass Star-forming Regions: Our View of the Milky Way
Trigonometric Parallaxes of High-mass Star-forming Regions: Our View of the Milky Way
复制标题
高质量恒星形成区域的三角视差：我们对银河系的看法
DOI：
10.3847/1538-4357/ab4a11
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发表时间：
2019
影响因子：
4.9
通讯作者：
van Langevelde H. J.
中科院分区：
文献类型：
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作者：
Reid M. J.;Menten K. M.;Brunthaler A.;Zheng X. W.;Dame T. M.;Xu Y.;Li J.;Sakai N.;Wu Y.;Immer K.;Zhang B.;Sanna A.;Moscadelli L.;Rygl K. L. J.;Bartkiewicz A.;Hu B.;Quiroga-Nunez L. H.;van Langevelde H. J.
我们编译和分析了大约200个三角函数的扰动和分子脉泽的自行与非常年轻的大质量恒星。大多数测量来自使用VLBA和日本VERA项目的BeSSeL调查。这些测量结果强烈表明，银河系是一个四臂螺旋，有一些额外的臂段和马刺。将对数周期螺旋线与脉泽的位置相匹配，允许螺旋线中的“扭结”，并使用银河系第四象限中公认的臂切线，使我们能够显着扩展我们对银河系结构的看法。我们提出了一个更新的模型，其螺旋结构，并将其纳入我们以前发表的基于螺旋臂的距离估计程序与螺旋臂的来源。对三维空间运动的建模产生了到银河系中心的距离，太阳位置的圆周旋转速度，km s-1，以及旋转曲线的性质。我们的数据强烈地限制了太阳的圆周速度km s−1和角速度km s−1 kpc-1。将测量到的空间运动转换到与银河系一起旋转的银河系中心坐标系，我们发现非圆速度分量通常为10 km s-1。然而，在银河酒吧附近和英仙座手臂的一部分，我们发现了显着更大的非圆形运动。在银河系中心7千秒差距以内的年轻大质量恒星，其标度高度只有19秒差距，因此非常适合定义银河平面。我们发现该平面的方位与IAU定义的平面在±0.°1内一致，并且太阳向银河系北极偏移pc。考虑到这种偏移，中央超大质量黑洞Sgr A* 位于银河系的中平面。测量到的垂直于银河系平面的运动将该平面在太阳半径处的岁差限制在0.44 km s-1。利用我们改进的银河系参数，我们预测Hulse-Taylor脉冲双星的距离为6.54 ± 0.24 kpc，假设它的轨道衰减来自引力辐射遵循广义相对论。
We compile and analyze approximately 200 trigonometric parallaxes and proper motions of molecular masers associated with very young high-mass stars. Most of the measurements come from the BeSSeL Survey using the VLBA and the Japanese VERA project. These measurements strongly suggest that the Milky Way is a four-arm spiral, with some extra arm segments and spurs. Fitting log-periodic spirals to the locations of the masers, allowing for “kinks” in the spirals and using well-established arm tangencies in the fourth Galactic quadrant, allows us to significantly expand our view of the structure of the Milky Way. We present an updated model for its spiral structure and incorporate it into our previously published parallax-based distance-estimation program for sources associated with spiral arms. Modeling the three-dimensional space motions yields estimates of the distance to the Galactic center, , the circular rotation speed at the Sun's position, km s−1, and the nature of the rotation curve. Our data strongly constrain the full circular velocity of the Sun, km s−1, and its angular velocity, km s−1 kpc–1. Transforming the measured space motions to a Galactocentric frame which rotates with the Galaxy, we find non-circular velocity components typically ≲10 km s−1. However, near the Galactic bar and in a portion of the Perseus arm we find significantly larger non-circular motions. Young high-mass stars within 7 kpc of the Galactic center have a scale height of only 19 pc, and thus are well suited to define the Galactic plane. We find that the orientation of the plane is consistent with the IAU-defined plane to within ±0.°1, and that the Sun is offset toward the north Galactic pole by pc. Accounting for this offset places the central supermassive black hole, Sgr A*, in the midplane of the Galaxy. The measured motions perpendicular to the plane of the Galaxy limit precession of the plane to ≲4 km s−1 at the radius of the Sun. Using our improved Galactic parameters, we predict the Hulse–Taylor binary pulsar to be at a distance of 6.54 ± 0.24 kpc, assuming its orbital decay from gravitational radiation follows general relativity.