Mapping the Galactic Disk with the LAMOST and Gaia Red Clump Sample. VI. Evidence for the Long-lived Nonsteady Warp of Nongravitational Scenarios
Mapping the Galactic Disk with the LAMOST and Gaia Red Clump Sample. VI. Evidence for the Long-lived Nonsteady Warp of Nongravitational Scenarios
复制标题
使用 LAMOST 和盖亚红丛样本绘制银河盘图。
DOI：
10.3847/1538-4357/ab93ad
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发表时间：
2020
影响因子：
4.9
通讯作者：
Chen B-Q
中科院分区：
文献类型：
--
作者：
Wang H-F;Lopez-Corredoira M.;Huang Y.;Chang J.;Zhang H-W;Carlin J. L.;Chen X-D;Chrobakova Z.;Chen B-Q
通过将LAMOST DR4和Gaia DR2普通红团星与年龄和自行相结合，我们用一个简单的模型分析了不受任何假设的恒星翘曲的振幅演化。在不同的恒星群中，曲盘的最大高度随着银心距离的增加而增加，并与年龄有关：年轻恒星群表现出比老年恒星群更强的曲折特征，并伴随着曲折幅度γ(AGE)随年龄的减小，其一阶导数不同于零。节线ϕw的方位角在−5°处是稳定的，没有明显的时间演化，这很好地证实了前人的一些工作。所有这些自相矛盾的证据都支持我们的银河系翘曲很可能是一种长期但不稳定的结构，而不是一种暂时的结构，这支持了翘曲起源于气体流入圆盘或其他假设，这些假说认为翘曲主要影响气体，因此追踪气体的年轻群体比年长的群体更强大。换句话说，银河系翘曲是由盘面模型上的非引力相互作用引起的。
By combining LAMOST DR4 and Gaia DR2 common red clump stars with age and proper motion, we analyze the amplitude evolution of the stellar warp independently of any assumption with a simple model. The greatest height of the warp disk increases with galactocentric distance in different populations and is dependent on age: the younger stellar populations exhibit stronger warp features than the old ones, accompanied by the warp amplitude γ (age) decreasing with age, and its first derivative is different from zero. The azimuth of the line of nodes ϕw is stable at −5° without clear time evolution, which perfectly confirms some previous works. All of this self-consistent evidence supports that our Galactic warp should most likely be a long-lived but nonsteady structure and not a transient one, which is supporting that the warp originated from gas infall onto the disk or other hypotheses that suppose that the warp mainly affects the gas, and consequently, younger populations tracing the gas are stronger than older ones. In other words, the Galactic warp is induced by the nongravitational interaction over the disk models.