Multiple Stellar Populations in the Globular Cluster omega Centauri as Tracers of a Merger Event

Abstract

The discovery of the Sagittarius dwarf galaxy, which is being tidally disrupted by and merging with the Milky Way, supports the view that the halo of the Galaxy has been built up at least partially by the accretion of similar dwarf systems. The Sagittarius dwarf contains several distinct populations of stars, and includes M54 as its nucleus, which is the second most massive globular cluster associated with the Milky Way. The most massive globular cluster is omega Centauri, and here we report that omega Centauri also has several distinct stellar populations, as traced by red-giant-branch stars. The most metal-rich red-giant-branch stars are about 2 Gyr younger than the dominant metal-poor component, indicating that omega Centauri was enriched over this timescale. The presence of more than one epoch of star formation in a globular cluster is quite surprising, and suggests that omega Centauri was once part of a more massive system that merged with the Milky Way, as the Sagittarius dwarf galaxy is in the process of doing now. Mergers probably were much more frequent in the early history of the Galaxy and omega Centauri appears to be a relict of this era.

7 pages, 3 figures, Latex+nature.sty (included), To appear in November 4th issue of Nature

Cited by in corpus (255)

• Star Formation Histories, Abundances and Kinematics of Dwarf Galaxies in the Local Group
• The New Galaxy: Signatures of its Formation
• Co-formation of the Galactic disc and the stellar halo
• Multiple populations in globular clusters. Lessons learned from the Milky Way globular clusters
• The Faintest Dwarf Galaxies
• Omega Centauri: The Population Puzzle Goes Deeper
• Evidence for Two Early Accretion Events That Built the Milky Way Stellar Halo
• The ACS Survey of Galactic Globular Clusters. VII. Relative Ages
• The ACS Survey of Galactic Globular Clusters. IX. Horizontal Branch Morphology and the Second Parameter Phenomenon
• Metallicities on the Double Main Sequence of omega Centauri Imply Large Helium Enhancement
• Spectroscopic and Photometric evidence of two stellar populations in the Galactic Globular Cluster NGC6121 (M4)
• 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)
• Fitting the integrated Spectral Energy Distributions of Galaxies
• A helium spread among the main sequence stars in NGC 2808
• The dynamical distance and intrinsic structure of the globular cluster omega Centauri
• A Complete Spectroscopic Survey of the Milky Way Satellite Segue 1: The Darkest Galaxy
• The stellar halo of the Galaxy
• The E-MOSAICS Project: simulating the formation and co-evolution of galaxies and their star cluster populations
• "Galaxy," Defined
• New evidence for the complex struscture of the RGB of Omega Cen
• Super Helium-Rich Population and the Origin of Extreme Horizontal-Branch Stars in Globular Clusters
• Flash Mixing on the White Dwarf Cooling Curve: Understanding Hot Horizontal Branch Anomalies in NGC 2808
• Photometric signatures of multiple stellar populations in Galactic globular clusters
• Origin of multiple stellar populations in globular clusters and their helium enrichment
• Enrichment by supernovae in globular clusters with multiple populations
• A double stellar generation in the Globular Cluster NGC6656 (M 22). Two stellar groups with different iron and s-process element abundance
• Sodium-oxygen anticorrelation and neutron capture elements in Omega Centauri stellar populations
• Hubble Space Telescope reveals multiple Sub-Giant Branch in eight Globular Clusters
• The State-of-the-Art HST Astro-Photometric Analysis of the core of $\omega$ Centauri. I. The Catalog
• Accretion relicts in the solar neighbourhood: debris from omegaCen's parent galaxy
• Willman 1 - a probable dwarf galaxy with an irregular kinematic distribution
• The Unique History of the Globular Cluster Omega Centauri
• Homogeneous photometry VII. Globular clusters in the Gaia era
• The Bizarre Chemical Inventory of NGC 2419, An Extreme Outer Halo Globular Cluster
• Characterizing the Chemistry of the Milky Way Stellar Halo: Detailed Chemical Analysis of a Metal-Poor Stellar Stream
• Mixed Populations in Globular Clusters: Et Tu, 47 Tuc?
• Metallicities, relative ages and kinematics of stellar populations in omega Centauri
• Globular cluster systems in nearby dwarf galaxies - II. Nuclear star clusters and their relation to massive Galactic globular clusters
• Cluster AgeS Experiment: The Age and Distance of the Globular Cluster omega Centauri Determined from Observations of the Eclipsing Binary OGLEGC17
• New HST WFC3/UVIS observations augment the stellar-population complexity of omega Centauri
• Radial distribution of the multiple stellar populations in omega Centauri
• The Helium abundance and Delta Y / Delta Z in Lower Main Sequence stars
• The HST large programme on $\omega$ Centauri - II. internal kinematics
• The last breath of the Sagittarius dSph
• High resolution spectroscopy of metal rich giants in omega Cen: first indication of SNe Ia enrichment
• Multiple stellar populations in the Galactic globular cluster NGC 6752
• The C+N+O abundance of Omega Centauri giant stars: implications on the chemical enrichment scenario and the relative ages of different stellar populations
• Contribution of stripped nuclear clusters to globular cluster and ultra-compact dwarf galaxy populations
• The Presence of Two Distinct Red Giant Branches in the Globular Cluster NGC 1851
• The Observed and Predicted Spatial Distribution of Milky Way Satellite Galaxies
• Kinematic Decoupling of Globular Clusters with Extended Horizontal-Branch
• The pure non-collisional Blue Straggler population in the giant stellar system omega Centauri
• Ceci n'est pas a globular cluster: the metallicity distribution of the stellar system Terzan 5
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XXIII. Proper-motion catalogs and internal kinematics
• Hubble Space Telescope Observations of an Outer Field in Omega Centauri: A Definitive Helium Abundance
• Giants in the globular cluster omega Centauri: dust production, mass loss and distance
• Reconstructing the Disrupted Dwarf Galaxy $Gaia$-Sausage/Enceladus Using its Stars and Globular Clusters
• Another Non-segregated Blue Straggler Population in a Globular Cluster: the Case of NGC 2419
• Population Parameters of Intermediate-Age Star Clusters in the Large Magellanic Cloud. II. New Insights from Extended Main Sequence Turnoffs in 7 Star Clusters
• Discovery of an anomalous Sub Giant Branch in the Color Magnitude Diagram of omega Centauri
• A near-infrared spectroscopic screening of the red giant populations in omega Centauri
• A Spectroscopic Analysis of the Galactic Globular Cluster NGC 6273 (M19)
• Identification of A Transient Neutron Star in Quiescence in the Globular Cluster NGC 5139
• The fraction of globular cluster second-generation stars in the Galactic halo
• Structural Parameters for Globular Clusters in NGC 5128
• The Accreted Nuclear Clusters of the Milky Way
• Exploring Halo Substructure with Giant Stars: Substructure in the Local Halo as Seen in the Grid Giant Star Survey Including Extended Tidal Debris from Omega Centauri
• Galactic Halo Stars in Phase Space :A Hint of Satellite Accretion?
• Low-resolution spectroscopy of main sequence stars belonging to 12 Galactic globular clusters. I. CH and CN band strength variations
• The Gaia-ESO Survey: Stellar content and elemental abundances in the massive cluster NGC 6705
• Star Formation Histories of Globular Clusters with Multiple Populations. I. ω Cen, M22, and NGC 1851
• Direct Evidence for an Enhancement of Helium in Giant Stars in Omega Centauri
• The State-of-the-Art HST Astro-Photometric Analysis of the core of ωCentauri. III. The Main Sequence's Multiple Populations Galore
• Population Parameters of Intermediate-Age Star Clusters in the Large Magellanic Cloud. III. Dynamical Evidence for a Range of Ages Being Responsible for Extended Main Sequence Turnoffs
• Accretion of gas by globular cluster stars
• The Rotation of Sub-Populations in omega Centauri
• The evolution of two stellar populations in globular clusters I. The dynamical mixing timescale
• A deep view into the nucleus of the Sagittarius Dwarf Spheroidal Galaxy with MUSE. I. Data and stellar population characterization
• CCD Photometry of the Globular Cluster omega Centauri. II. Stellar Populations and Age-Metallicity Relation
• Fe and Al Abundances for 180 Red Giants in the Globular Cluster Omega Centauri (NGC 5139)
• On the Origin of Sub-subgiant Stars. I. Demographics
• Formation of globular clusters in atomic-cooling halos via rapid gas condensation and fragmentation during the epoch of reionization
• Abundances of lithium, oxygen, and sodium in the turn-off stars of Galactic globular cluster 47 Tuc
• CCD Photometry of the Globular Cluster Omega Centauri. I. Metallicity of RR Lyrae Stars from Caby Photometry
• The Age and Metallicity Relation of Omega Centauri
• Remnants of Sagittarius Dwarf Spheroidal Galaxy around the young globular cluster Palomar 12
• A Large Sample Study of Red Giants in the Globular Cluster Omega Centauri (NGC 5139)
• Diversity of nuclear star cluster formation mechanisms revealed by their star formation histories
• The HST Large Program on Omega Centauri. I. Multiple stellar populations at the bottom of the main sequence probed in NIR-Optical
• 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
• Evolution of second generation stars in stellar disks of globular and nuclear clusters: Omega Centauri as a test case
• The ACS Fornax Cluster Survey. IX. The Color-Magnitude Relation of Globular Cluster Systems
• Age as the Second Parameter in NGC 288 / NGC 362? I. Turnoff Ages: a Purely Differential Comparison
• Fast Winds and Mass Loss from Metal-Poor Field Giants
• Formation of Second Generation Stars in Globular Clusters
• Radial anisotropy in omega Cen limiting the room for an intermediate-mass black hole
• A Spitzer Space Telescope Atlas of omega Centauri: The Stellar Population, Mass Loss, and the Intracluster Medium
• The lithium content of omega Centauri. New clues to the cosmological Li problem from old stars in external galaxies
• The Frequency of Large Radius Hot and Very Hot Jupiters in omega Centauri
• Ground-based CCD astrometry with wide field imagers. III. [email protected] proper-motion catalog of the globular cluster omega Centauri
• The Milky Way without X: An alternative interpretation of the double red clump in the Galactic bulge
• Stromgren photometry of Galactic Globular Clusters. II Metallicity distribution of red giants in Omega Centauri
• The multiple stellar population in omega Centauri: spatial distribution and structural properties
• Are Globular Clusters the Remnant Nuclei of Progenitor Disk Galaxies?
• Extended Star Clusters in the Remote Halo of the Intriguing Dwarf Galaxy NGC 6822
• Stellar Models of Multiple Populations in Globular Clusters. I. The Main Sequence of NGC 6752
• Discovery of an accreted stellar system within the globular cluster omega Centauri
• Multiple Stellar Populations of Globular Clusters from Homogenous Ca by Photometry I. M22 (NGC 6656)
• Radial velocities in the globular cluster omega Centauri
• Using globular clusters to test gravity in the weak acceleration regime
• UV Properties of Galactic Globular Clusters with GALEX II. Integrated colors
• Chemical Abundances of the Leo II Dwarf Galaxy
• Two Groups of Red Giants with Distinct Chemical Abundances in the Bulge Globular Cluster NGC 6553 Through the Eyes of APOGEE
• The mosaic multiple stellar populations in $\omega$ Centauri : the Horizontal Branch and the Main Sequence
• Reddening distribution across the center of the globular cluster Omega Centauri
• YZiCS: Preprocessing of dark halos in the hydrodynamic zoom-in simulation of clusters
• A spectral atlas of post-main-sequence stars in omega Centauri: kinematics, evolution, enrichment and interstellar medium
• Nonlinear Color-Metallicity Relations of Globular Clusters. III. On the Discrepancy in Metallicity between Globular Cluster Systems and their Parent Elliptical Galaxies
• On the Origin of Bimodal Horizontal-Branches in Massive Globular Clusters: The Case of NGC 6388 and NGC 6441
• Spectroscopic Signatures of Extra-Tidal Stars Around the Globular Clusters NGC 6656 (M22), NGC 3201 and NGC 1851 from RAVE
• The chemical evolution of Omega Centauri's progenitor system
• A critical look at the merger scenario to explain multiple populations and rotation in iron-complex globular clusters
• A wide-field photometric survey for extratidal tails around five metal-poor globular clusters in the Galactic halo
• The origin of the 'blue tilt' of globular cluster populations in the E-MOSAICS simulations
• Yonsei Evolutionary Population Synthesis (YEPS) Model. I. Spectroscopic Evolution of Simple Stellar Populations
• Multiple stellar populations of globular clusters from homogeneous Ca-Cn photometry. II. M5 (NGC 5904) and a new filter system
• Lithium abundances in red giants of M4: evidence for asymptotic giant branch star pollution in globular clusters?
• Multiple stellar populations and their evolution in globular clusters: A nucleosynthesis perspective
• A Deep Wide-Field Variable Star Catalog of Omega Centauri
• The oxygen vs. sodium (anti)correlation(s) in omega Cen
• A Deep X-ray Survey of the Globular Cluster Omega Centauri
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. VIII. Preliminary Public Catalog Release
• Hot Horizontal Branch stars in omega Centauri: clues about their origin from the cluster Color Magnitude Diagram
• Some Musings on Globular Cluster Systems
• Intermediate-Mass Black Holes in Early Globular Clusters
• A deep view into the nucleus of the Sagittarius Dwarf Spheroidal Galaxy with MUSE. II. Kinematic characterization of the stellar populations
• Ejection of globular cluster interstellar media through ionization by white dwarfs
• Multiple stellar populations in the globular cluster M3 (NGC 5272): a Strömgren perspective
• The subgiant branch of omega Cen seen through high-resolution spectroscopy. I. The first stellar generation in omega Centauri?
• Low-resolution Spectroscopy for the Globular Clusters with Signs of Supernova Enrichment: M22, NGC 1851 and NGC 288
• The State-of-the-Art HST Astro-Photometric Analysis of the core of $\omega$ Centauri. II. Differential-Reddening Map
• Discovery of Blue Hook Stars in the Massive Globular Cluster M54
• Homogeneous Analysis of Globular Clusters from the APOGEE Survey with the BACCHUS Code $-$ III. $\omega$ Cen
• Yonsei evolutionary population synthesis (YEPS). II. Spectro-photometric evolution of helium-enhanced stellar populations
• Evolution of Binary Stars in Multiple-Population Globular Clusters
• Self-consistent analysis of stellar clusters: An application to HST data of the halo globular cluster NGC 6752
• Nonlinear Color-Metallicity Relations of Globular Clusters. II. A Test on the Nonlinearity Scenario for Color Bimodality Using the u-band Colors: The Case of M87 (NGC 4486)
• Chemical enrichment mechanisms in Omega Centauri: clues from neutron-capture elements
• 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
• 2MASS Studies of Differential Reddening Across Three Massive Globular Clusters
• Two Distinct Red Giant Branches in the Globular Cluster NGC 288
• HST/ACS Imaging of Omega Centauri: Optical Counterparts of Chandra X-Ray Sources
• Medium resolution spectroscopy in Omega Centauri: abundances of 400 subgiant and turn-off region
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XX. Ages of single and multiple stellar populations in seven bulge globular clusters
• Gaia and Hubble unveil the kinematics of stellar populations in the Type II globular clusters ω Centauri and M 22
• Analysis of medium resolution spectra by automated methods - application to M55 and omega Centauri
• Abundances on the Main Sequence of Omega Centauri
• Explaining the multiple populations in globular clusters by multiple episodes of star formation and enrichment without gas expulsion from massive star feedback
• The Most Metal-poor Stars in Omega Centauri (NGC 5139)
• The dynamical origin of multiple populations in intermediate-age clusters in the Magellanic Clouds
• On the metallicity distribution of the peculiar globular cluster M22
• Chromosome maps of Globular Clusters from wide-field ground-based photometry
• On the separation between RR Lyrae and Type II Cepheids and their importance for distance determination: the case of $\omega$ Cen
• Discovery of more than two thousand white dwarfs in the globular cluster Omega Centauri
• From the CMD of Omega Centauri and (super-)AGB stellar models to a Galactic plane passage gas purging chemical evolution scenario
• Confirmation and physical characterization of the new bulge globular cluster Patchick 99 from the VVV and Gaia surveys
• On the role of Type Ia supernovae in the second generation star formation in globular clusters
• RAVE stars tidally stripped/ejected from $\omega$ Centauri globular cluster
• MOCCA: Dynamics and evolution of binary stars of multiple stellar populations in tidally filling and underfilling globular star clusters
• IR photometric properties of Red Giants in omega Cen
• Mass segregation in the outer halo globular cluster Palomar 14
• The Relation between Near-Infrared Luminosity of RGB Bumps and Metallicity of Galactic Globular Clusters
• Globular cluster formation with multiple stellar populations from hierarchical star cluster complexes
• Clues to the formation of Liller 1 from modeling its complex star formation history
• Ultra-Compact Dwarfs around NGC 3268
• Evidence for metallicity spreads in three massive M31 globular clusters
• The evolutionary status of the blue hook stars in Omega Centauri
• Formation of globular clusters with multiple stellar populations from massive gas clumps in high-z gas-rich dwarf galaxies
• Spinning like a Blue Straggler: the population of fast rotating Blue Straggler stars in Omega Centauri
• oMEGACat III. Multi-band photometry and metallicities reveal spatially well-mixed populations within $\omega$ Centauri's half-light radius
• Detecting Axion Dark Matter through the Radio Signal from Omega Centauri
• Ongoing hierarchical massive cluster assembly: the LISCA II structure in the Perseus complex
• Assembling the Milky Way bulge from globular clusters: Evidence from the double red clump
• Abundances of C, N, Sr and Ba on the red giant branch of omega Centauri
• oMEGACat II -- Photometry and proper motions for 1.4 million stars in Omega Centauri and its rotation in the plane of the sky
• Binary interactions as a possible scenario for the formation of multiple stellar populations in globular clusters
• Confirming the intrinsic abundance spread in the globular cluster NGC 6273 (M 19) with calcium triplet spectroscopy
• Simulations of globular clusters within their parent galaxies: multiple stellar populations and internal kinematics
• Manganese Abundances in the Globular Cluster Omega Centauri
• The CN-CH positive correlation in the globular cluster NGC 5286
• A chromosome map to unveil stellar populations with different magnesium abundances. The case of Omega Centauri
• NGC 1261: an $r$-process enhanced globular cluster from the Gaia-Enceladus event
• Testing the AGB Scenario as the Origin of the Extreme-Helium Population in omega Centauri
• Blue Hook Stars in Globular Clusters
• Simulations of globular clusters within their parent galaxies: Metallicity spreads and anomalous precursor populations
• Abundance ties: Nephele and the globular cluster population accreted with $\omega$ Cen. Based on APOGEE DR17 and Gaia EDR3
• Contribution of stripped nuclei to the ultracompact dwarf galaxy population in the Virgo Cluster
• A stellar census in globular clusters with MUSE. A new perspective on the multiple main sequences of $\omega$ Centauri
• New cluster members and halo stars of the Galactic globular cluster NGC 1851
• Possible Streams of the Globular Clusters in the Galaxy
• Lithium abundance in lower red giant branch stars of Omega Centauri
• On the anomalous red giant branch of the globular cluster Omega Cen
• Spectral matching for abundances of 848 stars of the giant branches of the globular cluster ω Centauri
• oMEGACat. VI. Analysis of the overall kinematics of Omega Centauri in 3D: velocity dispersion, kinematic distance, anisotropy, and energy equipartition
• Kinematically Detected Halo Streams
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XIII. ACS/WFC Parallel-Field Catalogues
• SNe and their impact during the early evolution of Type I Globular Clusters
• The Science Case for PILOT III: the Nearby Universe
• Tidal stripping stellar substructures around four metal-poor globular clusters in the Galactic bulge
• On the early evolution of massive star clusters: the case of cloud D1 and its embedded cluster in NGC 5253
• Tidal debris from Omega Centauri discovered with unsupervised machine learning
• Spatial and kinematic segregation in star cluster merger remnants
• Multiple populations in globular clusters: Unified efforts from stellar evolution and chemical evolution models
• Is Terzan 5 the remnant of a building block of the Galactic bulge? Evidence from APOGEE
• Lithium in the lower red giant branch of 5 Galactic globular clusters
• Tidal features and disc thicknesses of edge-on galaxies in the SDSS Stripe 82
• Constraints on annihilating dark matter in the Omega Centauri cluster
• A new formation model for omega Centauri: the crossroad of astrophysical processes
• Three candidate double clusters in the LMC: truth or dare?
• Bayesian Analysis of Two Stellar Populations in Galactic Globular Clusters II: NGC 5024, NGC 5272, and NGC 6352
• Helium Enhancement in the Metal Rich Red Giants of Omega Centauri
• Exploring the Mass Segregation Effect of X-ray Sources in Globular Clusters. IV. Evidence of Black Hole Burning in $\omega$ Centauri
• Chemical evolution of star clusters
• Evidence for Enrichment by Supernovae in the Globular Cluster NGC 6273
• Diffusion and mixing in globular clusters
• Beryllium abundances in turn-off stars of globular clusters with the CUBES spectrograph
• An ongoing tidal capture in the Large Magellanic Cloud: the low-mass star cluster KMK88-10 captured by the massive globular cluster NGC 1835?
• Multiple Main Sequence of Globular Clusters as a Result of Inhomogeneous Big Bang Nucleosynthesis
• New sub-grouping of multiple stellar populations in NGC 2808 based on low-resolution spectroscopy
• Chemical composition of stellar populations in Omega Centauri
• Introducing a new multi-particle collision method for the evolution of dense stellar systems. Crash-test N-body simulations
• A Sr-Rich Star on the Main Sequence of Omega Centauri
• Black Hole Scaling Relations in the Dwarf-galaxy Regime with $Gaia$-Sausage/Enceladus and $\omega$Centauri
• Dating N loud AGNs at high redshift: GS3073 as a snapshot of wCen like evolution of a nuclear star cluster
• Kinematics of metallicity populations in Omega Centauri using Gaia Focused Product Release and Hubble Space Telescope
• Medium-resolution Spectroscopy of Red Giant Branch Stars in $\omega$ Centauri
• Omega Centauri: weak MgH-band in red giants directly trace the helium content
• The ACS survey of globular clusters. XIII. Photometric calibration in comparison with Stetson standards
• On the impossible NGC 4372 V1 and V2: an extended AGB to the [Fe/H] = -2.2 cluster
• The Origin of Young Stellar Populations in NGC 1783: Accretion of External Stars
• Observational dynamics of low-mass stellar systems
• On the formation of globular clusters: comparison with observations
• Chemical tagging with APOGEE, MUSE, and HST: constraints on the formation of $\omega$ Centauri
• Impact of radiation feedback on the assembly of star clusters in galactic context
• The Nephele ecosystem: stars, globular clusters, and stellar streams associated with the progenitor galaxy of $\omega$ Centauri
• Deciphering the Milky Way's star formation at cosmic noon with high proper-motion stars: A precursor to the merger-driven starburst
• The dynamical evolution of the stellar clumps in the Sparkler galaxy
• Double white dwarf binary population in MOCCA star clusters -- Comparisons with observations of close and wide binaries
• Synthetic spectroscopic indices for identifying multiple stellar populations in globular clusters
• FROST-CLUSTERS -- III. Metallicity-dependent intermediate mass black hole formation by runaway collisions in dense star clusters
• Purveyors of fine halos III. Chemical abundance analysis of a potential omega Cen associate
• The quite complex "Simple Stellar Populations" of Globular Clusters