We examine the vertical structure of Galactic disk kinematics over a Galactocentric radial distance range of R=5–15 kpc and up to 3 kpc away from the Galactic plane, using the K-type giants surveyed by LAMOST. Based on robust measurements of three-dimensional velocity moments, a wobbly disk is detected in a phenomenological sense. An outflow dominates the radial motion of the inner disk, while in the outer disk there exist alternate outward and inward flows. The vertical bulk velocities is a combination of breathing and bending modes. A contraction-like breathing mode with amplitudes increasing with the distance to the plane and an upward bending mode dominate the vertical motion outside R ₀, and there are reversed breathing and bending modes at R<R ₀, with amplitudes much smaller than those outside R ₀. The mean azimuthal velocity decreases with the increasing distance to the plane, with gradients shallower for larger R. Stars in the south disk are rotating faster than stars in the north. The velocity ellipsoid orientation differs between different R: in the range of , the gradient of the tilt angle with respect to decreases from ∼0.83 for the inner disk to ∼0.52 for the outer disk; within , the tilt of velocity ellipsoid deviates from vertical antisymmetry. A clear flaring signature is found for both north and south disks based on the observed vertical structures of velocity ellipsoid.

我们使用 LAMOST 调查的 K 型巨星，在R = 5-15 kpc的银河中心径向距离范围内以及距银河平面 3 kpc 的范围内检查银河盘运动学的垂直结构。基于对三维速度矩的稳健测量，在现象学意义上检测到了一个摆动的圆盘。流出主导着内盘的径向运动，而在外盘中存在交替的向外和向内流动。垂直体积速度是呼吸和弯曲模式的组合。甲收缩状与振幅与该平面的距离，并且向上弯曲模式支配的垂直方向运动以外增加呼吸模式- [R ₀，并有相反的呼吸，并在弯曲模式ř< R ₀，幅度远小于R ₀之外的幅度。平均方位角速度随着与平面距离的增加而降低，对于较大的R梯度更小。南盘的恒星比北盘的恒星旋转得更快。速度不同椭圆体之间的取向不同ř：在的范围内，倾斜角度的梯度相对于降低从~0.83用于内盘~0.52为外盘; 在 内，速度椭球的倾斜偏离垂直反对称。根据观察到的速度椭球体的垂直结构，发现了北和南两个圆盘的清晰的耀斑特征。