تقرير
A2A: 21,000 bulge stars from the ARGOS survey with stellar parameters on the APOGEE scale
| العنوان: | A2A: 21,000 bulge stars from the ARGOS survey with stellar parameters on the APOGEE scale |
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| المؤلفون: | Wylie, S. M., Gerhard, O. E., Ness, M. K., Clarke, J. P., Freeman, K. C., Bland-Hawthorn, J. |
| المصدر: | A&A 653, A143 (2021) |
| سنة النشر: | 2021 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics |
| الوصف: | We use the data-driven method, The Cannon, to bring 21,000 stars from the ARGOS bulge survey, including 10,000 red clump stars, onto the parameter and abundance scales of the cross-Galactic survey, APOGEE, obtaining rms precisions of 0.10 dex, 0.07 dex, 74 K, and 0.18 dex for [Fe/H], [Mg/Fe], Teff, and log(g), respectively. The re-calibrated ARGOS survey - which we refer to as the A2A survey - is combined with the APOGEE survey to investigate the abundance structure of the Galactic bulge. We find X-shaped [Fe/H] and [Mg/Fe] distributions in the bulge that are more pinched than the bulge density, a signature of its disk origin. The mean abundance along the major axis of the bar varies such that the stars are more [Fe/H]-poor and [Mg/Fe]-rich near the Galactic center than in the long bar/outer bulge region. The vertical [Fe/H] and [Mg/Fe] gradients vary between the inner bulge and long bar with the inner bulge showing a flattening near the plane that is absent in the long bar. The [Fe/H]-[Mg/Fe] distribution shows two main maxima, an ``[Fe/H]-poor [Mg/Fe]- rich'' maximum and an ``[Fe/H]-rich [Mg/Fe]-poor'' maximum, that vary in strength with position in the bulge. In particular, the outer long bar close to the Galactic plane is dominated by super-solar [Fe/H], [Mg/Fe]-normal stars. Stars composing the [Fe/H]-rich maximum show little kinematic dependence on [Fe/H], but for lower [Fe/H] the rotation and dispersion of the bulge increase slowly. Stars with [Fe/H]<-1 dex have a very different kinematic structure than stars with higher [Fe/H]. Comparing with recent models for the Galactic boxy-peanut bulge, the abundance gradients and distribution, and the relation between [Fe/H] and kinematics suggest that the stars comprising each maximum have separate disk origins with the ``[Fe/H]-poor [Mg/Fe]-rich'' stars originating from a thicker disk than the ``[Fe/H]-rich [Mg/Fe]-poor'' stars. Comment: 26 pages, 29 figures, revised version as submitted to A&A following referee report |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1051/0004-6361/202140990 |
| URL الوصول: | http://arxiv.org/abs/2106.14298 |
| رقم الأكسشن: | edsarx.2106.14298 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1051/0004-6361/202140990 |
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