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Using the multi-object adaptive optics demonstrator RAVEN to observe metal-poor stars in and towards the Galactic Centre

Lamb, M. ; Venn, K. ; Andersen, D. ; Oya, S. ; Shetrone, M. ; Fattahi, A. ; Howes, L. LU ; Asplund, M. ; Lardière, O. and Akiyama, M. , et al. (2017) In Monthly Notices of the Royal Astronomical Society 465(3). p.3536-3557
Abstract

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 [α/Fe]~+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.... (More)

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 [α/Fe]~+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 1σ, although one of these two stars has [Fe/H] = -2.01 ± 0.09, which is on the low end for this cluster. The [α/Fe] and [Ni/Fe] values differ by 2σ, 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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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Galaxy: centre, Globular clusters: individual: M22, Instrumentation: adaptive optics, Stars: abundances, Techniques: spectroscopic
in
Monthly Notices of the Royal Astronomical Society
volume
465
issue
3
pages
22 pages
publisher
Oxford University Press
external identifiers
  • scopus:85014705542
ISSN
0035-8711
DOI
10.1093/mnras/stw2865
language
English
LU publication?
yes
id
0aa77ffc-82eb-4c0c-aee4-148894198cd5
date added to LUP
2022-04-04 11:12:36
date last changed
2024-04-07 06:18:53
@article{0aa77ffc-82eb-4c0c-aee4-148894198cd5,
  abstract     = {{<p>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&lt;[Fe/H] &lt; -1.5, and high [α/Fe]~+0.3, typical of Galactic disc and bulge stars in this metallicity range; [Al/Fe] and [N/Fe] are also high, whereas [C/Fe] &lt; +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 1σ, although one of these two stars has [Fe/H] = -2.01 ± 0.09, which is on the low end for this cluster. The [α/Fe] and [Ni/Fe] values differ by 2σ, 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.</p>}},
  author       = {{Lamb, M. and Venn, K. and Andersen, D. and Oya, S. and Shetrone, M. and Fattahi, A. and Howes, L. and Asplund, M. and Lardière, O. and Akiyama, M. and Ono, Y. and Terada, H. and Hayano, Y. and Suzuki, G. and Blain, C. and Jackson, K. and Correia, C. and Youakim, K. and Bradley, C.}},
  issn         = {{0035-8711}},
  keywords     = {{Galaxy: centre; Globular clusters: individual: M22; Instrumentation: adaptive optics; Stars: abundances; Techniques: spectroscopic}},
  language     = {{eng}},
  number       = {{3}},
  pages        = {{3536--3557}},
  publisher    = {{Oxford University Press}},
  series       = {{Monthly Notices of the Royal Astronomical Society}},
  title        = {{Using the multi-object adaptive optics demonstrator RAVEN to observe metal-poor stars in and towards the Galactic Centre}},
  url          = {{http://dx.doi.org/10.1093/mnras/stw2865}},
  doi          = {{10.1093/mnras/stw2865}},
  volume       = {{465}},
  year         = {{2017}},
}