The Wobbly Galaxy : kinematics north and south with RAVE red-clump giants
The Wobbly Galaxy : kinematics north and south with RAVE red-clump giants
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DOI：
10.1093/mnras/stt1522
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发表时间：
2013-02
影响因子：
4.8
通讯作者：
M. Williams;M. Steinmetz;J. Binney;A. Siebert;H. Enke;B. Famaey;I. Minchev;R. D. Jong;C. Boeche
中科院分区：
文献类型：
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作者：
M. Williams;M. Steinmetz;J. Binney;A. Siebert;H. Enke;B. Famaey;I. Minchev;R. D. Jong;C. Boeche
RADIAL速度实验调查，结合自行和距离估计，可以用来详细研究恒星运动学在扩大的太阳附近（太阳郊区）。利用72365颗红团星，我们研究了6 <R <10 kpc和-2 <Z <2 kpc之间的3D平均速度分量，重点是南北差异。简单的参数拟合的（R，Z）的Vφ和速度分散的趋势。我们证实了最近发现的银河系中心径向速度VR的梯度，发现梯度在平面以下是明显的（当Z <0时，δ/δR = -8 km s-1 kpc-1，平面以上为零），因此也存在Z梯度。垂直速度，VZ，也显示了明确的，大幅度的（|VZ| = 17 km s-1）结构，具有稀疏-压缩模式的迹象，暗示波浪状行为。我们进行了严格的误差分析，跟踪系统和随机误差的来源。我们确认南北差异VR和VZ沿着视线，VR估计独立的自行。复杂的三维结构的速度空间提出了挑战，未来的银河系盘的建模，与银河棒，旋臂和激发波状结构都可能发挥作用。
The RAdial Velocity Experiment survey, combined with proper motions and distance estimates, can be used to study in detail stellar kinematics in the extended solar neighbourhood (solar suburb). Using 72 365 red-clump stars, we examine the mean velocity components in 3D between 6 <R <10 kpc and -2 <Z <2 kpc, concentrating on north-south differences. Simple parametric fits to the (R, Z) trends for Vφ and the velocity dispersions are presented. We confirm the recently discovered gradient in mean Galactocentric radial velocity, VR, finding that the gradient is marked below the plane (δ/δR = -8 km s-1 kpc-1 for Z <0, vanishing to zero above the plane), with a Z gradient thus also present. The vertical velocity, VZ, also shows clear, large-amplitude (|VZ| = 17 km s-1) structure, with indications of a rarefaction-compression pattern, suggestive of wave-like behaviour. We perform a rigorous error analysis, tracing sources of both systematic and random errors. We confirm the north-south differences in VR and VZ along the line of sight, with the VR estimated independent of the proper motions. The complex three-dimensional structure of velocity space presents challenges for future modelling of the Galactic disc, with the Galactic bar, spiral arms and excitation of wave-like structures all probably playing a role.