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Gaussian processes, median statistics, Milky Way rotation curves
Astrophysics and Space Science ( IF 1.8 ) Pub Date : 2020-08-01 , DOI: 10.1007/s10509-020-03858-7
Hai Yu , Aman Singal , Jacob Peyton , Sara Crandall , Bharat Ratra

We use the Iocco et al. (2015) compilation of 2,780 circular velocity measurements to analyze the Milky Way rotation curve. We find that the error bars for individual measurements are non-gaussian, and hence instead derive median statistics binned central circular velocity values and error bars from these data. We use these median statistics central values and error bars to fit the data to simple, few parameter, rotation curve functions. These simple functions are unable to adequately capture the significant small scale spatial structure in these data and so provide poor fits. We introduce and use the Gaussian Processes (GP) method to capture this small scale structure and use it to derive Milky Way rotation curves from the binned median statistics circular velocity data. The GP method rotation curves have significant small-scale spatial structure superimposed on a broad rise to galactocentric radius $R\approx7$ kpc and a decline at larger $R$. We use the GP method median statistics rotation curve to measure the Oort $A$ and $B$ constants and other characteristic rotation curve quantities. We study correlations in the residual circular velocities (relative to the GP method rotation curve). Along with other evidence for azimuthal asymmetry of the Milky Way circular rotation velocity field, we find that larger residual circular velocities seem to favor parts of spiral arms.

中文翻译:

高斯过程、中值统计、银河系旋转曲线

我们使用 Iocco 等人。(2015) 汇编了 2,780 个圆周速度测量值来分析银河系自转曲线。我们发现单个测量的误差线是非高斯的,因此从这些数据中导出中值统计合并中心圆速度值和误差线。我们使用这些中值统计中心值和误差线将数据拟合到简单的、参数少的旋转曲线函数。这些简单的函数无法充分捕捉这些数据中重要的小尺度空间结构,因此拟合效果不佳。我们引入并使用高斯过程 (GP) 方法来捕获这种小尺度结构,并使用它从分箱中值统计圆速度数据中导出银河系旋转曲线。GP 方法旋转曲线具有显着的小尺度空间结构,叠加在银河中心半径 $R\approx7$ kpc 的广泛上升和更大的 $R$ 下降。我们使用GP方法中值统计旋转曲线来测量奥尔特$A$和$B$常数和其他特征旋转曲线量。我们研究残余圆速度的相关性(相对于 GP 方法旋转曲线)。连同银河系圆形旋转速度场方位角不对称的其他证据,我们发现较大的剩余圆形速度似乎有利于旋臂的部分。我们研究残余圆速度的相关性(相对于 GP 方法旋转曲线)。连同银河系圆形旋转速度场方位角不对称的其他证据,我们发现较大的剩余圆形速度似乎有利于旋臂的部分。我们研究残余圆速度的相关性(相对于 GP 方法旋转曲线)。连同银河系圆形旋转速度场方位角不对称的其他证据,我们发现较大的剩余圆形速度似乎有利于旋臂的部分。
更新日期:2020-08-01
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