Gas and stellar motions and observational signatures of corotating spiral arms
Gas and stellar motions and observational signatures of corotating spiral arms
复制标题
DOI：
10.1093/mnras/stu1292
复制
发表时间：
2014-04
影响因子：
4.8
通讯作者：
D. Kawata;Jason A. S. Hunt;R. Grand;S. Pasetto;M. C. Mssl;Ucl
中科院分区：
文献类型：
--
作者：
D. Kawata;Jason A. S. Hunt;R. Grand;S. Pasetto;M. C. Mssl;Ucl
我们已经观察到我们的N体/平滑粒子流体动力学模拟银河系大小的棒旋星系的快照，以类似的方式，我们可以观察银河系。模拟的星系显示了一个共转的旋臂，即旋臂以与圆周速度相同的速度旋转。我们观察到气体和恒星的旋转和径向速度是从我们假设的观察者在圆盘平面上的三条视线（l，B）=（90，0），（120，0）和（150，0）度的距离的函数。我们发现，由于径向迁移，恒星倾向于在旋臂后面（前面）旋转得更慢（更快），并向外（向内）移动。然而，由于它们的震中运动，我们看到绕旋臂的旋转和径向速度的变化，另一方面，由于径向迁移，冷气体成分在旋臂后面（前面）表现出更明显的旋转慢（快）和向外（向内）移动的趋势。我们将所得结果与Reid等人的脉泽源速度进行了比较，并发现观测数据在l = 120 °处围绕螺旋臂的预期位置的旋转速度方面显示出类似的趋势。我们还比较了径向速度的分布，从当地标准的休息，V，与阿帕奇点天文台星系演化实验（APOGEE）的数据在l = 90度作为一个例子。© 2014作者由牛津大学出版社代表皇家天文学会出版。
We have observed a snapshot of our N-body/smoothed particle hydrodynamics simulation of a Milky Way-sized barred spiral galaxy in a similar way to how we can observe the Milky Way. The simulated galaxy shows a corotating spiral arm, i.e. the spiral arm rotates with the same speed as the circular speed. We observed the rotation and radial velocities of the gas and stars as a function of the distance from our assumed location of the observer at the three lines of sight on the disc plane, (l, b) = (90, 0), (120, 0) and (150, 0) deg. We find that the stars tend to rotate slower (faster) behind (at the front of) the spiral arm and move outwards (inwards), because of the radial migration. However, because of their epicycle motion, we see a variation of rotation and radial velocities around the spiral arm. On the other hand, the cold gas component shows a clearer trend of rotating slower (faster) and moving outwards (inwards) behind (at the front of) the spiral arm, because of the radial migration. We have compared the results with the velocity of the maser sources from Reid et al., and find that the observational data show a similar trend in the rotation velocity around the expected position of the spiral arm at l = 120 deg. We also compared the distribution of the radial velocity from the local standard of the rest, V, with the Apache Point Observatory Galactic Evolution Experiment (APOGEE) data at l = 90 deg as an example. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.