论文标题
银河系的棒和螺旋臂：结构和运动学
The Bar and Spiral Arms in the Milky Way: Structure and Kinematics
论文作者
论文摘要
银河系是一个带有Schechter特征光度$ l _*$的螺旋星系，因此是所有螺旋星系的哈勃序列的重要锚点。然而，几个世纪以来，银河系的真实外观一直难以捉摸。我们回顾了当前对家庭银河系的结构和运动学的最佳理解，并在螺旋臂的几乎所有组件以及太阳透视上的COBE图像中对银河系结构进行了科学上的精确可视化。银河系包含一个坚固的条，四个主要的螺旋臂和一个额外的手臂（当地手臂），可能比以前想象的要长。我们观察到的银河式凸出凸起主要是花生形的中央棒，几乎末端的圆形角度从太阳 - 半乳酸中心线处为25-30度。条形从中央花生形结构平稳过渡到左右左右的薄薄部分。银河凸起/棒包含银河系中总恒星质量的30-40％。恒星和气体运动学的动态建模产生的条形图旋转速度约为35-40 km/s/kpc，对应于〜160-180 MYR的条形旋转周期。从银河系的角度来看，我们的银河系可能是一个纯净的银河系，几乎没有空间进行重大合并的“经典”球体凸起，我们给出了许多原因。
The Milky Way is a spiral galaxy with the Schechter characteristic luminosity $L_*$, thus an important anchor point of the Hubble sequence of all spiral galaxies. Yet the true appearance of the Milky Way has remained elusive for centuries. We review the current best understanding of the structure and kinematics of our home galaxy, and present an updated scientifically accurate visualization of the Milky Way structure with almost all components of the spiral arms, along with the COBE image in the solar perspective. The Milky Way contains a strong bar, four major spiral arms, and an additional arm segment (the Local arm) that may be longer than previously thought. The Galactic boxy bulge that we observe is mostly the peanut-shaped central bar viewed nearly end-on with a bar angle of 25-30 degrees from the Sun-Galactic center line. The bar transitions smoothly from a central peanut-shaped structure to an extended thin part that ends around R ~ 5 kpc. The Galactic bulge/bar contains ~ 30-40% of the total stellar mass in the Galaxy. Dynamical modelling of both the stellar and gas kinematics yields a bar pattern rotation speed of ~ 35-40 km/s/kpc, corresponding to a bar rotation period of ~ 160-180 Myr. From a galaxy formation point of view, our Milky Way is probably a pure-disk galaxy with little room for a significant merger-made, "classical" spheroidal bulge, and we give a number of reasons why this is the case.
