Homogeneous Analysis of Globular Clusters from the APOGEE Survey with the BACCHUS Code $-$ III. $\omega$ Cen

Abstract

We study the multiple populations of $\omega$ Cen by using the abundances of Fe, C, N, O, Mg, Al, Si, K, Ca, and Ce from the high-resolution, high signal-to-noise (S/N$>$70) spectra of 982 red giant stars observed by the SDSS-IV/APOGEE-2 survey. We find that the shape of the Al-Mg and N-C anticorrelations changes as a function of metallicity, continuous for the metal-poor groups, but bimodal (or unimodal) at high metallicities. There are four Fe populations, similar to what has been found in previously published investigations, but we find seven populations based on Fe, Al, and Mg abundances. The evolution of Al in $\omega$ Cen is compared to its evolution in the Milky Way and in five representative globular clusters. We find that the distribution of Al in metal-rich stars of $\omega$ Cen closely follows what is observed in the Galaxy. Other $\alpha -$elements and C, N, O, and Ce are also compared to the Milky Way, and significantly elevated abundances are observed over what is found in the thick disk for almost all elements. However, we also find some stars with high metallicity and low [Al/Fe], suggesting that $\omega$ Cen could be the remnant core of a dwarf galaxy, but the existence of these peculiar stars needs an independent confirmation. We also confirm the increase in the sum of CNO as a function of metallicity previously reported in the literature and find that the [C/N] ratio appears to show opposite correlations between Al-poor and Al-rich stars as a function of metallicity.

arXiv commentAccepted for publication in MNRAS, 17 pages, 16 figures, 3 tables

References in corpus (51)

• The chemical composition of the Sun
• Gaia Data Release 2. Summary of the contents and survey properties
• The Apache Point Observatory Galactic Evolution Experiment (APOGEE)
• The Sixteenth Data Release of the Sloan Digital Sky Surveys: First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra
• Astrophysics Source Code Library
• Na-O Anticorrelation and HB. VII. The chemical composition of first and second-generation stars in 15 globular clusters from GIRAFFE spectra
• A Triple Main Sequence in the Globular Cluster NGC 2808
• Intrinsic iron spread and a new metallicity scale for Globular Clusters
• Multiple Stellar Populations in Globular Clusters
• Na-O Anticorrelation and HB. VIII. Proton-capture elements and metallicities in 17 globular clusters from UVES spectra
• A catalogue of masses, structural parameters and velocity dispersion profiles of 112 Milky Way globular clusters
• The ACS Survey of Galactic Globular Clusters. I. Overview and Clusters Without Previous HST Photometry
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. I. Overview of the Project and Detection of Multiple Stellar Populations
• APOGEE Data and Spectral Analysis from SDSS Data Release 16: Seven Years of Observations Including First Results from APOGEE-South
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. IX. The Atlas of Multiple Stellar Populations
• Multiple Stellar Populations in the Globular Cluster omega Centauri as Tracers of a Merger Event
• Formation of omega Centauri from an ancient nucleated dwarf galaxy in the young Galactic disc
• Chemical Abundances for 855 Giants in the Globular Cluster Omega Centauri (NGC 5139)
• Thermohaline instability and rotation-induced mixing. III - Grid of stellar models and asymptotic asteroseismic quantities from the pre-main sequence up to the AGB for low- and intermediate-mass stars at various metallicities
• New evidence for the complex struscture of the RGB of Omega Cen
• Chemical tagging with APOGEE: Discovery of a large population of N-rich stars in the inner Galaxy
• The Streams of the Gaping Abyss: A population of entangled stellar streams surrounding the Inner Galaxy
• Homogeneous Analysis of Globular Clusters from the APOGEE Survey with the BACCHUS Code. II. The Southern Clusters and Overview
• Sodium-oxygen anticorrelation and neutron capture elements in Omega Centauri stellar populations
• Exploring Anticorrelations and Light Element Variations in Northern Globular Clusters Observed by the APOGEE Survey
• The Gaia-ESO Survey. Mg-Al anti-correlation in iDR4 globular clusters
• Disentangling the Galactic Halo with APOGEE: I. Chemical and Kinematical Investigation of Distinct Metal-Poor Populations
• New HST WFC3/UVIS observations augment the stellar-population complexity of omega Centauri
• High resolution spectroscopy of metal rich giants in omega Cen: first indication of SNe Ia enrichment
• The C+N+O abundance of Omega Centauri giant stars: implications on the chemical enrichment scenario and the relative ages of different stellar populations
• The Chemical Compositions of Accreted and {\it in situ} Galactic Globular Clusters According to SDSS/APOGEE
• APOGEE Chemical Abundances of Globular Cluster Giants in the Inner Galaxy
• A homogeneous analysis of globular clusters from the APOGEE survey with the BACCHUS code. I. The Northern clusters
• Hubble Space Telescope Observations of an Outer Field in Omega Centauri: A Definitive Helium Abundance
• Atypical Mg-poor Milky Way field stars with globular cluster second-generation like chemical patterns
• Chemical abundances in the nucleus of the Sagittarius dwarf spheroidal galaxy
• Chemical tagging can work: Identification of stellar phase-space structures purely by chemical-abundance similarity
• Direct Evaluation of the Helium Abundances in Omega Centauri
• Multiple populations in Omega Centauri: a cluster analysis of spectroscopic data
• The multiple stellar population in omega Centauri: spatial distribution and structural properties
• Mergers of Globular Clusters
• Two Groups of Red Giants with Distinct Chemical Abundances in the Bulge Globular Cluster NGC 6553 Through the Eyes of APOGEE
• The contribution of N-rich stars to the Galactic stellar halo using APOGEE red giants
• Aluminium abundances in five discrete stellar populations of the globular cluster NGC 2808
• Evidence of AGB pollution in Galactic globular clusters from the Mg-Al anticorrelations observed by the APOGEE survey
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. VIII. Preliminary Public Catalog Release
• Spatial metallicity asymmetry in $\omega$ Centauri
• The not so simple globular cluster $\omega$ Cen. I. Spatial distribution of the multiple stellar populations
• Carbon Isotopic Abundances in the Red Giants of Omega Centauri (NGC5139)
• Mergers, tidal interactions, and mass exchange in a population of disc globular clusters: II. Long-term evolution
• Abundances of C, N, Sr and Ba on the red giant branch of omega Centauri

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• CAPOS: The bulge Cluster APOgee Survey V. Elemental abundances of the bulge globular cluster HP 1
• APOGEE-2S Mg-Al anti-correlation of the Metal-Poor Globular Cluster NGC 2298
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