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THE IMPRINTS OF THE GALACTIC BAR ON THE THICK DISK WITH RAVE

机译:带有锐舞的厚碟上银河条的印记

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We study the kinematics of a local sample of stars, located within a cylinder of 500 pc radius centered on the Sun, in the RAVE data set. We find clear asymmetries in the v(R) - v(phi) velocity distributions of thin and thick disk stars: there are more stars moving radially outward for low azimuthal velocities and more radially inward for high azimuthal velocities. Such asymmetries have been previously reported for the thin disk as being due to the Galactic bar, but this is the first time that the same type of structures are seen in the thick disk. Our findings imply that the velocities of thick-disk stars should no longer be described by Schwarzschild's, multivariate Gaussian or purely axisymmetric distributions. Furthermore, the nature of previously reported substructures in the thick disk needs to be revisited as these could be associated with dynamical resonances rather than to accretion events. It is clear that dynamical models of the Galaxy must fit the 3D velocity distributions of the disks, rather than the projected 1D, if we are to understand the Galaxy fully.
机译:我们在RAVE数据集中研究了位于恒星周围500 pc半径的圆柱内的本地恒星样本的运动学。我们在薄圆盘星和厚圆盘星的v(R)-v(phi)速度分布中发现了明显的不对称性:对于低方位角速度,有更多的恒星径向向外移动,对于高方位角速度,有更多径向向内移动。先前已经报道了这种薄磁盘的不对称性,这是由于银河条造成的,但这是第一次在厚磁盘中看到相同类型的结构。我们的发现表明,厚盘恒星的速度不再应该用Schwarzschild的,多元高斯分布或纯轴对称分布来描述。此外,需要重新讨论厚盘中先前报告的子结构的性质,因为这些子结构可能与动态共振有关,而不是与吸积事件有关。很明显,如果我们要完全了解银河系,那么银河系的动力学模型必须适合磁盘的3D速度分布,而不是预计的1D。

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