The Galactic Bulge Radial Velocity/Abundance Assay

被引:0
|
作者
Rich, R. Michael [1 ]
机构
[1] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA
关键词
MILKY-WAY; VELOCITY ASSAY; BAADES WINDOW; M-STARS; GIANTS; KINEMATICS; EVOLUTION; ALPHA; II;
D O I
暂无
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
The Bulge Radial Velocity Assay (BRAVA) measured radial velocities for similar to 9500 late-type giants in the Galactic bulge, predominantly from -10 degrees < l < +10 degrees and -2 degrees < b < -10 degrees. The project has discovered that the bulge exhibits cylindrical rotation characteristic of bars, and two studies of dynamics (Shen et al. 2010; Wang et al. 2012 MNRAS sub.) find that bar models- either N-body formed from an instability in a preexisting disk, or a self-consistent model- can account for the observed kinematics. Studies of the Plaut field at (l, b) = 0 degrees, -8 degrees show that alpha enhancement is found in bulge giants even 1 kpc from the nucleus. New infrared studies extending to within 0.25 degrees = 35 pc of the Galactic Center find no iron or alpha gradient from Baade's Window (l, b) = 0.9 degrees, -3.9 degrees to our innermost field, in contrast to the marked gradient observed in the outer bulge. We consider the case of the remarkable globular cluster Terzan 5, which has a strongly bimodal iron and [alpha/Fe] within its members, and we consider evidence pro and con that the bulge was assembled from dissolved clusters. The Subaru telescope has the potential to contribute to study of the Galactic bulge, especially using the Hyper Superime-Cam and planned spectroscopic modes, as well as the high resolution spectrograph. The planned Jasmine satellite series may deliver a comprehensive survey of distances and proper motions of bulge stars, and insight into the origin and importance of the X-shaped bulge.
引用
收藏
页码:185 / 190
页数:6
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