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We present an abundance analysis of eight potential member stars of the old Galactic bulge globular cluster NGC6522. The same stars have previously been studied by Chiappini et al. (2011), who found very high abundances of the slow neutron…

星系天体物理 · 物理学 2015-06-22 Melissa Ness , Martin Asplund , Andrew R. Casey

Star clusters, particularly those objects in the disk-bulge-halo interface are as of yet poorly charted, albeit carrying important information about the formation and the structure of the Milky Way. Here, we present a detailed chemical…

星系天体物理 · 物理学 2017-12-27 Andreas Koch , Terese T. Hansen , Andrea Kunder

The radial profiles of the Hb, Mg, and Fe line-strength indices are presented for a sample of eight spiral galaxies with a low surface-brightness stellar disc and a bulge. The correlations between the central values of the line-strength…

宇宙学与河外天体物理 · 物理学 2015-06-04 L. Morelli , E. M. Corsini , A. Pizzella , E. Dalla Bontà , L. Coccato , J. Méndez-Abreu , M. Cesetti

A chemical characterization of the Galactic Center is essential for understanding its formation and structural evolution. Trends of alpha-elements, such as Mg, Si, and Ca, serve as powerful diagnostic tools, offering insights into…

We investigate the inner regions of the Milky Way with a sample of unprecedented size and coverage thanks to APOGEE DR16 and Gaia EDR3 data. Our inner Galactic sample has more than 26,000 stars within $|X_{\rm Gal}| <5$ kpc, $|Y_{\rm Gal}|…

[Abridged abstract] We have performed an abundance analysis for 176 F- and G- dwarfs of the Galactic thick disk component. Using accurate radial velocities combined with $Hipparcos$ astrometry, kinematics (U, V, and W) and Galactic orbital…

天体物理学 · 物理学 2009-11-13 Bacham E. Reddy , David L. Lambert , Carlos Allende Prieto

Context. Galactic Globular Clusters (GCs) are essential tools to understand the earliest epoch of the Milky Way, since they are among the oldest objects in the Universe and can be used to trace its formation and evolution. Current studies…

太阳与恒星天体物理 · 物理学 2017-09-06 C. Muñoz , S. Villanova , D. Geisler , I. Saviane , B. Dias , R. E. Cohen , F. Mauro

We selected Bulge stars from APOGEE DR17 cross-matched with astrometric data from \textit{Gaia} DR3. Bulge stars were divided into sub-samples with line-of-sight velocity dispersion analyzed and the peaks of MDF were detected by both…

星系天体物理 · 物理学 2025-10-29 Haoyang Liu , Cuihua Du , Zhongcheng Li , Jian Zhang , Mingji Deng

The atmospheric parameters and abundances of Mg, Si, Ca, and Ti have been determined for 20 stars using the Gaia DR2 parallaxes, high-resolution spectra, and the non-local thermodynamic equilibrium (non-LTE) line formation modeling. A…

太阳与恒星天体物理 · 物理学 2019-09-04 Lyudmila Mashonkina , Maria Neretina , Tatyana Sitnova , Yuri Pakhomov

The carbon, nitrogen, and oxygen abundances and trends in the bulge are discussed in the context of our recent analysis of these elements in an on-going project based on near-IR spectra (Ryde et al. 2009). We obtained these using the CRIRES…

星系天体物理 · 物理学 2015-05-14 N. Ryde

We present a detailed study of the composition of 20 M giants in the Galactic center with 15 of them confirmed to be in the Nuclear Star Cluster. As a control sample we have also observed 7 M giants in the Milky Way Disk with similar…

Abundances of alpha-elements such as Ca and Mg in disk and halo stars are usually derived from equivalent widths lines measured on high resolution spectra, and assuming Local Thermodynamic Equilibrium (LTE) . In this paper, we present…

天体物理学 · 物理学 2009-10-31 T. Idiart , F. Thevenin

The present sample of nearby bulgelike dwarf stars has kinematics and metallicities characteristic of a probable inner disk or bulge origin. Ages derived by using isochrones give 10-11 Gyr for these stars and metallicities are in the range…

天体物理学 · 物理学 2009-11-07 Luciana Pompeia , Beatriz Barbuy , Michel Grenon

The latest edition of the APOGEE-2/DR14 survey catalogue and the first \texttt{Payne} data release of APOGEE abundance determinations by Ting et al. are examined. We identify 31 previously unremarked metal-poor giant stars with anomalously…

To better understand the origin and evolution of the Milky Way bulge, we have conducted a survey of bulge red giant branch and clump stars using the HERMES spectrograph on the Anglo-Australian Telescope. We targeted ARGOS survey stars with…

星系天体物理 · 物理学 2019-05-01 L. Duong , M. Asplund , D. M. Nataf , K. C. Freeman , M. Ness , L. M. Howes

Stellar atmospheric element abundance ratios of stars retain information about their birth conditions, helping elucidate their origin and nature. In this letter, we analyse and contrast the hydrostatic and explosive $\alpha$-element…

星系天体物理 · 物理学 2025-08-28 Danny Horta , Melissa K. Ness

We present alpha to iron abundance ratios for 226 individual red giant branch stars in nine dwarf galaxies of the Andromeda (M 31) satellite system. The abundances are measured from the combined signal of Mg, Si, Ca, and Ti lines in…

星系天体物理 · 物理学 2015-06-19 Luis C. Vargas , Marla C. Geha , Erik J. Tollerud

The inner Galaxy is the most complex region of the Milky Way, comprising the bulge, inner thin and thick discs, and inner halo; the formation of the bar transferred gas and stars from the disc inward. Accretion of dwarf galaxies also…

The characteristics of the stellar populations in the Galactic Bulge inform and constrain the Milky Way's formation and evolution. The metal-poor population is particularly important in light of cosmological simulations, which predict that…

We present a comprehensive chemical abundance analysis of five red giants and two horizontal branch (HB) stars towards the southern Galactic bulge, at (l,b)$\sim$(0$^{\rm o}$,-11$^{\rm o}$). Based on high-resolution spectroscopy obtained…

星系天体物理 · 物理学 2016-03-16 Andreas Koch , Andrew McWilliam , George W. Preston , Ian B. Thompson