Growing Local arm inferred by the breathing motion
Growing Local arm inferred by the breathing motion
复制标题
通过呼吸运动推断局部手臂正在生长
DOI：
10.1093/mnrasl/slad190
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Asano T
中科院分区：
文献类型：
--
作者：
Asano T
旋臂的理论模型表明，旋臂在盘状恒星中引起了垂直的大块运动。利用gaiadr3分析了呼吸运动，即围绕银河系盘中部的相干不对称垂直运动，我们发现在局部臂上存在压缩呼吸运动。另一方面，通过对一个孤立的类银河系盘状星系的anN-body模拟，我们发现瞬态和动态旋臂在旋臂生长阶段会产生压缩呼吸运动，而在断裂阶段则会出现扩张呼吸运动。观察到的压缩呼吸运动与局部臂的清晰对齐与模拟螺旋臂生长阶段所看到的相似。因此，我们认为局部臂的压缩呼吸运动可以用局部臂处于瞬态动态螺旋臂的生长阶段来解释。我们还发现了与英仙座臂相关的扩张呼吸运动的初步特征，以及与压缩呼吸运动相一致的外臂。这可以推断英仙座和外臂分别处于分裂和生长阶段。
Theoretical models of spiral arms suggest that the spiral arms provoke a vertical bulk motion in disc stars. By analysing the breathing motion, a coherent asymmetric vertical motion around the mid-plane of the Milky Way disc, withGaiaDR3, we found that a compressing breathing motion presents along the Local arm. On the other hand, with anN-body simulation of an isolated Milky Way-like disc galaxy, we found that the transient and dynamic spiral arms induce compressing breathing motions when the arms are in the growth phase, while the expanding breathing motion appears in the disruption phase. The observed clear alignment of the compressing breathing motion with the Local arm is similar to what is seen in the growth phase of the simulated spiral arms. Hence, we suggest that the Local arm’s compressing breathing motion can be explained by the Local arm being in the growth phase of a transient and dynamic spiral arm. We also identified the tentative signatures of the expanding breathing motion associated with the Perseus arm and also the Outer arm coinciding with the compressing breathing motion. This may infer that the Perseus and Outer arms are in the disruption and growth phases, respectively.