Formation of massive globular clusters with heavy element abundance spread in the Galactic building blocks

Abstract

A growing number of recent observations have revealed that the Galactic globular cluster (GC) omega Cen is not the only GC that shows abundance spread in heavy elements (e.g., Fe). In order to understand the origin of the Galactic GCs with heavy element abundance spread ("HEAS"), we investigate the formation processes of massive GCs (MGCs) with masses larger than 10^6 M_sun in gas-rich dwarf galaxies interacting and merging with the very young Galaxy. We find that massive and compact stellar clumps with masses larger than 10^6 M_sun, which can be regarded as progenitors of MGCs, can form from massive gas clumps that are developed through merging of gaseous regions initially at different regions and thus with different metallicities. Therefore it is inevitable that MGCs formed in dwarfs have HEAS. The abundance spread in each individual MGC depends on the radial metallicity gradient of the host dwarf such that it can be larger for the steeper metallicity gradient. For example, MGCs formed in a dwarf with a central metallicity of [Fe/H]=-1.1 and the radial gradient of -0.2 dex kpc^{-1} can have the abundance spread of Delta [Fe/H] ~.2. The simulated MGCs appear to be significantly flattened owing to their dissipative formation from gas disks of their host dwarfs. Based on these results, we discuss possibly diverse formation mechanisms for the Galactic GCs such as M22, M54, NGC 2419, omega Cen, and Terzan 5.

5pages, 5 figures, accepted in MNRAS (LETTERS)

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Cited by in corpus (11)

• Star Formation Histories of Globular Clusters with Multiple Populations. I. ω Cen, M22, and NGC 1851
• Accretion of pristine gas and dilution during the formation of multiple-population globular clusters
• The Milky Way without X: An alternative interpretation of the double red clump in the Galactic bulge
• Gas depletion in primordial globular clusters due to accretion onto stellar-mass black holes
• CN Anomalies in the Halo System and the Origin of Globular Clusters in the Milky Way
• The role of rotation on the formation of second generation stars in globular clusters
• On the role of Type Ia supernovae in the second generation star formation in globular clusters
• Mergers of multi-metallic globular clusters: The role of dynamics
• Formation of globular clusters with multiple stellar populations from massive gas clumps in high-z gas-rich dwarf galaxies
• Peeking beneath the precision floor I: metallicity spreads and multiple elemental dispersions in the globular clusters NGC 288 and NGC 362
• Initial Li Abundances in the Protogalaxy and Globular Clusters Based upon the Chemical Separation and Hierarchical Structure Formation