论文标题
Gaia数据版本2的本地恒星速度场的高斯过程模型2
Gaussian Process Model for the Local Stellar Velocity Field from Gaia Data Release 2
论文作者
论文摘要
我们使用GAIA的第二个数据释放中的4M恒星的位置和速度测量值对局部恒星速度场进行建模。我们确定〜27K空间定义的垃圾箱中平均速度或大容量速度的成分。我们的假设是，这些量构成了高斯过程，其中简单协方差函数或内核描述了不同位置的散装速度之间的相关性。我们使用基于诱导点的稀疏高斯过程算法来构建基础速度场的非参数，平滑和可区分的模型。我们估计Oort常数A，B，C和K，并找到与先前结果非常吻合的值。速度场的地图在2 kpc的太阳范围内显示出复杂的子结构，这提供了明确的证据，表明局部磁盘处于不平衡状态。我们介绍了恒星速度场差异的第一个3D图，并确定可能正在经历压缩和稀疏性的磁盘的区域。
We model the local stellar velocity field using position and velocity measurements for 4M stars from the second data release of Gaia. We determine the components of the mean or bulk velocity in ~27k spatially-defined bins. Our assumption is that these quantities constitute a Gaussian process where the correlation between the bulk velocity at different locations is described by a simple covariance function or kernel. We use a sparse Gaussian process algorithm based on inducing points to construct a non-parametric, smooth, and differentiable model for the underlying velocity field. We estimate the Oort constants A, B, C, and K and find values in excellent agreement with previous results. Maps of the velocity field within 2 kpc of the Sun reveal complicated substructures, which provide clear evidence that the local disk is in a state of disequilibrium. We present the first 3D map of the divergence of the stellar velocity field and identify regions of the disk that may be undergoing compression and rarefaction.
