Star Formation Histories of Globular Clusters with Multiple Populations. I. ω Cen, M22, and NGC 1851

Abstract

There is increasing evidence that some massive globular clusters (GCs) host multiple stellar populations having different heavy element abundances enriched by supernovae. They usually accompany multiple red giant branches (RGBs) in the color-magnitude diagrams (CMDs), and are distinguished from most of the other GCs which display variations only in light element abundances. In order to investigate the star formation histories of these peculiar GCs, we have constructed synthetic CMDs for ω Cen, M22, and NGC 1851. Our models are based on the updated versions of Yonsei-Yale (Y^2) isochrones and horizontal branch (HB) evolutionary tracks which include the cases of enhancements in both helium and the total CNO abundances. To estimate ages and helium abundances of subpopulations in each GC, we have compared our models with the observations on the Hess diagram by employing a χ^2 minimization technique. We find that metal-rich subpopulations in each of these GCs are also enhanced in helium abundance, and the age differences between the metal-rich and metal-poor subpopulations are fairly small (~0.3-1.7 Gyr), even in the models with the observed variations in the total CNO content. These are required to simultaneously reproduce the observed extended HB and the splits on the main sequence, subgiant branch, and RGB. Our results are consistent with the hypothesis that these GCs are the relics of more massive primeval dwarf galaxies that merged and disrupted to form the proto-Galaxy.

40 pages, 16 figures, 4 tables, accepted for publication in ApJ

References in corpus (23)

• Fast rotating massive stars and the origin of the abundance patterns in galactic globular clusters
• The ACS Survey of Galactic Globular Clusters. I. Overview and Clusters Without Previous HST Photometry
• Spectroscopic and Photometric evidence of two stellar populations in the Galactic Globular Cluster NGC6121 (M4)
• The ACS Survey of Galactic Globular Clusters. III. The Double Subgiant Branch of NGC 1851
• The ACS Survey of Galactic Globular Clusters: M54 and Young Populations in the Sagittarius Dwarf Spheroidal Galaxy
• Origin of multiple stellar populations in globular clusters and their helium enrichment
• The double Subgiant Branch of NGC 1851: the role of the CNO abundance
• An abundance analysis of bright giants in the globular cluster NGC 1851
• Stellar Models with Enhanced Abundances of C, N, O, Ne, Na, Mg, Si, S, Ca, and Ti, in Turn, at Constant Helium and Iron Abundances
• The influence of residual gas expulsion on the evolution of the Galactic globular cluster system and the origin of the Population II halo
• A large C+N+O abundance spread in giant stars of the globular cluster NGC 1851
• Deep FORS1 observations of the double Main Sequence of omega Centauri
• A model for the Globular Cluster extreme anomalies
• Kinematic Decoupling of Globular Clusters with Extended Horizontal-Branch
• Fe and Al Abundances for 180 Red Giants in the Globular Cluster Omega Centauri (NGC 5139)
• New Metallicities of RR Lyrae Stars in omega Centauri: Evidence for a Non He-Enhanced Metal-Intermediate Population
• MCAO near-IR photometry of the Globular Cluster NGC 6388: MAD observations in crowded fields
• Are Globular Clusters the Remnant Nuclei of Progenitor Disk Galaxies?
• On the Origin of Bimodal Horizontal-Branches in Massive Globular Clusters: The Case of NGC 6388 and NGC 6441
• The chemical evolution of Omega Centauri's progenitor system
• Multi-wavelength Hubble Space Telescope photometry of stellar populations in NGC288
• The Horizontal Branch of NGC 1851: Constraints on the Cluster Subpopulations
• On the effect of helium enhancement on bolometric corrections and Teff-colour relations

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• Multiple Stellar Populations in Globular Clusters
• Evidence for Two Early Accretion Events That Built the Milky Way Stellar Halo
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• Early-type Host Galaxies of Type Ia Supernovae. II. Evidence for Luminosity Evolution in Supernova Cosmology
• The metallicity spread and the age-metallicity relation of Omega Centauri
• CNO abundances in the globular clusters NGC 1851 and NGC 6752
• The RR Lyrae variables and Horizontal Branch of NGC6656 (M22)
• Formation of globular clusters in atomic-cooling halos via rapid gas condensation and fragmentation during the epoch of reionization
• Direct Evaluation of the Helium Abundances in Omega Centauri
• The Milky Way without X: An alternative interpretation of the double red clump in the Galactic bulge
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. IV. Helium content and relative age of multiple stellar populations within NGC 6352
• Multiple Stellar Populations of Globular Clusters from Homogenous Ca by Photometry I. M22 (NGC 6656)
• The mosaic multiple stellar populations in $\omega$ Centauri : the Horizontal Branch and the Main Sequence
• Space Velocities of Southern Globular Clusters VII. NGC 6397, NGC 6626 (M 28) and NGC 6656 (M 22)
• Nucleosynthesis in helium-enriched asymptotic giant branch models: Implications for Heavy Element Enrichment in Omega Centauri
• Low-resolution Spectroscopy for the Globular Clusters with Signs of Supernova Enrichment: M22, NGC 1851 and NGC 288
• Yonsei evolutionary population synthesis (YEPS). II. Spectro-photometric evolution of helium-enhanced stellar populations
• Multiple Populations in Globular Clusters and the Origin of the Oosterhoff Period Groups
• Two distinct red giant branch populations in the globular cluster NGC 2419 as tracers of a merger event in the Milky Way
• New insight on the origin of the double red clump in the Milky Way bulge
• The complex stellar system M 22: confirming abundance variations with high precision differential measurements
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XX. Ages of single and multiple stellar populations in seven bulge globular clusters
• The Na-O anticorrelation in horizontal branch stars. IV. M22
• The evolution of white dwarfs resulting from helium-enhanced, low-metallicity progenitor stars
• oMEGACat I: MUSE spectroscopy of 300,000 stars within the half-light radius of $\omega$ Centauri
• On the metallicity distribution of the peculiar globular cluster M22
• Evolution and nucleosynthesis of helium-rich asymptotic giant branch models
• Uncovering Multiple Populations with Washington Photometry: I. The Globular Cluster NGC 1851
• An Updated Census of RR~Lyrae Stars in the Globular Cluster $\omega$~Centauri (NGC\,5139)
• Globular cluster systems as tracers of the evolutionary history in NGC 3258 and NGC 3268
• Nuclear Star Clusters in Cosmological Simulations
• The period-age relation of long-period variables
• Mass loss of different stellar populations in Globular Clusters: the case of M4
• The Gaia-ESO Survey: Detailed Abundances in the Metal-poor Globular Cluster NGC 4372
• Common Origin of Two RR Lyrae Populations and the Double Red Clump in the Milky Way Bulge
• The Horizontal Branch population of NGC 1851 as revealed by the Ultra-violet Imaging Telescope (UVIT)
• Bayesian Analysis of Two Stellar Populations in Galactic Globular Clusters III: Analysis of 30 Clusters
• The s-Process Enrichment of the Globular Clusters M4 and M22
• oMEGACat III. Multi-band photometry and metallicities reveal spatially well-mixed populations within $\omega$ Centauri's half-light radius
• oMEGACat II -- Photometry and proper motions for 1.4 million stars in Omega Centauri and its rotation in the plane of the sky
• G2C2 - IV: A novel approach to study the radial distributions of multiple populations in Galactic globular clusters
• STREGA: STRucture and Evolution of the GAlaxy. I. Survey Overview and First Results
• RR Lyrae Variable Stars in the Crater II Dwarf Galaxy
• Near-IR period-luminosity relations for pulsating stars in $\omega$ Centauri (NGC 5139)
• Early-type Host Galaxies of Type Ia Supernovae. I. Evidence for Downsizing
• On the origin of the gamma-ray emission from Omega Centauri: Milisecond pulsars and dark matter annihilation
• The effect of second generation populations on the integrated colors of metal-rich globular clusters in early-type galaxies
• Five Stellar Populations in M22 (NGC 6656)
• Stellar populations in $\omega$ Centauri: a multivariate analysis
• oMEGACat. VI. Analysis of the overall kinematics of Omega Centauri in 3D: velocity dispersion, kinematic distance, anisotropy, and energy equipartition
• SHOTGLAS II. MUSE spectroscopy of blue horizontal branch stars in the core of $\omega$ Centauri and NGC 6752
• Multiple populations in globular clusters: Unified efforts from stellar evolution and chemical evolution models
• RR Lyrae Stars in the Field of Sagittarius II
• A Possible Relic Star Cluster in the Sextans Dwarf Galaxy
• Hubble Space Telescope FUV observations of M31's globular clusters suggest a spatially homogeneous helium-enriched sub population
• Multiple Populations in NGC 1851: Abundance Variations and UV Photometric Synthesis in the Washington and HST/WFC3 Systems
• Evolutionary history of four binary blue stragglers from the globular clusters ωCen, M55, 47 Tuc and NGC 6752
• Light Element Chemistry and the Double Red Giant Branch in the Galactic Globular Cluster NGC 288
• Globular Cluster UVIT legacy Survey (GlobUleS) III. Omega Centauri in Far-Ultraviolet
• Core collapse and horizontal-branch morphology in galactic globular clusters
• On the Use of the Number Count of Blue Horizontal--Branch Stars to Infer the Dominant Building Blocks of the Milky Way Halo
• The Populations of Carina. I. Decoding the Color--Magnitude Diagram
• The complex stellar system M 22: constraining the chemical enrichment from AGB stars using magnesium isotope ratios