Is the Milky Way still breathing? RAVE–Gaia streaming motions
Is the Milky Way still breathing? RAVE–Gaia streaming motions
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DOI：
10.1093/mnras/stx3342
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发表时间：
2017-10
影响因子：
4.8
通讯作者：
I. Carrillo;I. Minchev;G. Kordopatis;M. Steinmetz;J. Binney;F. Anders;O. Bienaym'e;J. Bland-Hawthorn-J.-Bl
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文献类型：
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作者：
I. Carrillo;I. Minchev;G. Kordopatis;M. Steinmetz;J. Binney;F. Anders;O. Bienaym'e;J. Bland-Hawthorn-J.-Bl
我们使用径向速度实验（RAVE）和Tycho-Gaia天体测量解决方案（TGAS）目录的数据来计算由相关银心速度的径向（VR），方位角（V）和垂直（Vz）分量产生的速度场。我们搜索特别是在所有三个速度分量的变化与上方和下方的光盘中平面的距离，以及如何每个组件的VZ（视线和切向速度投影）修改所获得的垂直结构。为了研究速度对自行和距离的依赖性，我们使用两个主要样本：一个RAVE样本，包括Tycho-2，PPMXL和UCAC 4星表的自行，以及一个RAVE-TGAS样本，从TGAS和UCAC 5星表推断距离和自行。在这两个样本中，我们发现了VR和Vz的不对称性。在该平面以下，我们发现最大的径向梯度为0.01 ± 0.61 km s-1 kpc-1，与最近的研究一致。在平面上方，我们发现一个类似的梯度，即Δ VR/Δ R = -9.42 ± 1.77 km s-1 kpc-1。通过比较我们的结果与以前的研究，我们发现，在Vz的结构是强烈依赖于所采用的自行。使用银河系模型，我们证明了距离的不确定性可以创建人工波浪状图案。与之前在RAVE数据中看到的呼吸模式的建议相反，我们的结果支持弯曲和呼吸模式的组合，可能由外部或内部和外部机制的组合产生。（减）
We use data from the Radial Velocity Experiment (RAVE) and the Tycho-Gaia astrometric solution (TGAS) catalogue to compute the velocity fields yielded by the radial (VR), azimuthal (Vϕ),and vertical (Vz) components of associated Galactocentric velocity. We search in particular for variation in all three velocity components with distance above and below the disc midplane, as well as how each component of Vz (line-of-sight and tangential velocity projections) modifies the obtained vertical structure. To study the dependence of velocity on proper motion and distance, we use two main samples: a RAVE sample including proper motions from the Tycho-2, PPMXL, and UCAC4 catalogues, and a RAVE-TGAS sample with inferred distances and proper motions from the TGAS and UCAC5 catalogues. In both samples, we identify asymmetries in VR and Vz. Below the plane, we find the largest radial gradient to be ∂VR/∂R = -7.01 ± 0.61 km s-1 kpc-1, in agreement with recent studies. Above the plane, we find a similar gradient with ∂VR/∂R = -9.42 ± 1.77 km s-1 kpc-1. By comparing our results with previous studies, we find that the structure in Vz is strongly dependent on the adopted proper motions. Using the Galaxia Milky Way model, we demonstrate that distance uncertainties can create artificial wave-like patterns. In contrast to previous suggestions of a breathing mode seen in RAVE data, our results support a combination of bending and breathing modes, likely generated by a combination of external or internal and external mechanisms. (Less)