期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 465, 期 3, 页码 3536-3557出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stw2865
关键词
instrumentation: adaptive optics; techniques: spectroscopic; stars: abundances; Galaxy: centre; globular clusters: individual: M22
资金
- NSERC Discovery Grant
- Grants-in-Aid for Scientific Research [26287027] Funding Source: KAKEN
The chemical abundances for five metal-poor stars in and towards the Galactic bulge have been determined from the H-band infrared spectroscopy taken with the RAVEN multi-object adaptive optics science demonstrator and the Infrared Camera and Spectrograph at the Subaru 8.2- m telescope. Three of these stars are in the Galactic bulge and have metallicities between - 2.1<[Fe/H]< - 1.5, and high [alpha/ Fe]similar to+ 0.3, typical of Galactic disc and bulge stars in this metallicity range; [Al/ Fe] and [N/ Fe] are also high, whereas [C/ Fe] < + 0.3. An examination of their orbits suggests that two of these stars may be confined to the Galactic bulge and one is a halo trespasser, though proper motion values used to calculate orbits are quite uncertain. An additional two stars in the globular cluster M22 show [ Fe/H] values consistent to within 1 sigma, although one of these two stars has [ Fe/H] = - 2.01 +/- 0.09, which is on the low end for this cluster. The [a/ Fe] and [Ni/ Fe] values differ by 2 sigma, with the most metal-poor star showing significantly higher values for these elements. M22 is known to show element abundance variations, consistent with a multipopulation scenario though our results cannot discriminate this clearly given our abundance uncertainties. This is the first science demonstration of multiobject adaptive optics with high-resolution infrared spectroscopy, and we also discuss the feasibility of this technique for use in the upcoming era of 30-m class telescope facilities.
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