HST proper motions on the far side of the Galactic bar—data
HST proper motions on the far side of the Galactic bar—data
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DOI：
10.1093/mnras/stad1911
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发表时间：
2023-06
影响因子：
4.8
通讯作者：
M. Soto;K. Kuijken;R. Rich;W. Clarkson;J. L. Nilo Castellón-J.-L.-Nilo Castellón-2125996717;J. G. Fernández-Trincado;R. Contreras Ramos-R.-C
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文献类型：
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作者：
M. Soto;K. Kuijken;R. Rich;W. Clarkson;J. L. Nilo Castellón-J.-L.-Nilo Castellón-2125996717;J. G. Fernández-Trincado;R. Contreras Ramos-R.-C
这是一系列论文中的第三篇，该系列论文试图利用低前景消光窗口中凸出恒星种群的运动学观测来观察银河系棒/凸出的清晰特征。我们报告的检测100000个新的自行在四个领域覆盖的银河酒吧/凸起的远侧，在负角速度。我们的自行是使用哈勃太空望远镜（HST）上的高级巡天照相机（ACS）的观测获得的，时间基线为8-9年，对于F814 W < 23 mag.有趣的是，如以前的工作所示，赫斯图显示了一个惊人的相似的自行分布领域更接近银河系中心和一致的旧恒星人口。观察到的运动学指向一个显著的凸起旋转，它似乎甚至在l −8°的磁场中占主导地位，并且也反映在l，B平面中速度椭球作为距离函数的变化中。
This is the third paper in a series that attempts to observe a clear signature of the Galactic bar/bulge using kinematic observations of the bulge stellar populations in low foreground extinction windows. We report on the detection of ∼100 000 new proper motions in four fields covering the far side of the Galactic bar/bulge, at negative longitudes. Our proper motions have been obtained using observations from the Advance Camera for Surveys (ACS), on board of the Hubble Space Telescope (HST), with a time-baseline of 8–9 years, which has produced accuracies better than 0.5 mas yr−1 for a significant fraction of the stellar populations with F814W < 23 mag. Interestingly, as shown in previous works, the Hess diagrams show a strikingly similar proper motion distribution to fields closer to the Galactic center and consistent with an old stellar population. The observed kinematics point to a significant bulge rotation, which seems to predominate even in fields as far as l ≃ −8°, and is also reflected in the changes of the velocity ellipsoid in the l, b plane as a function of distance.