Globular cluster metallicity distributions in the E-MOSAICS simulations

The metallicity distributions of globular cluster (GC) systems in galaxies are a critical test of any GC formation scenario. In this work, we investigate the predicted GC metallicity distributions of galaxies in the MOdelling Star cluster population Assembly In Cosmological Simulations within EAGLE...

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Main Authors: Pfeffer, Joel (Author) , Kruijssen, J M Diederik (Author) , Bastian, Nate (Author) , Crain, Robert A (Author) , Trujillo-Gomez, Sebastian (Author)
Format: Article (Journal)
Language:English
Published: 2023 January 9
In: Monthly notices of the Royal Astronomical Society
Year: 2023, Volume: 519, Issue: 4, Pages: 5384-5401
ISSN:1365-2966
DOI:10.1093/mnras/stad044
Online Access:Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1093/mnras/stad044
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Author Notes:Joel Pfeffer, J.M. Diederik Kruijssen, Nate Bastian, Robert A. Crain and Sebastian Trujillo-Gomez
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Summary:The metallicity distributions of globular cluster (GC) systems in galaxies are a critical test of any GC formation scenario. In this work, we investigate the predicted GC metallicity distributions of galaxies in the MOdelling Star cluster population Assembly In Cosmological Simulations within EAGLE (E-MOSAICS) simulation of a representative cosmological volume (L = 34.4 comoving Mpc). We find that the predicted GC metallicity distributions and median metallicities from the fiducial E-MOSAICS GC formation model agree well the observed distributions, except for galaxies with masses M∗ ∼ 2 × 10 10 M⊙, which contain an overabundance of metal-rich GCs. The predicted fraction of galaxies with bimodal GC metallicity distributions (37 ± 2 per cent in total; 45 ± 7 per cent for M∗ > 10 10.5 M⊙) is in good agreement with observed fractions (44+10 per cent), as are the mean metallicities of the metal-poor and metal-rich peaks. We show that, for massive galaxies (M∗ > 10 10 M⊙), bimodal GC distributions primarily occur as a result of cluster disruption from initially-unimodal distributions, rather than as a result of cluster formation processes. Based on the distribution of field stars with GC-like abundances in the Milky Way, we suggest that the bimodal GC metallicity distribution of Milky Way GCs also occurred as a result of cluster disruption, rather than formation processes. We conclude that separate formation processes are not required to explain metal-poor and metal-rich GCs, and that GCs can be considered as the surviving analogues of young massive star clusters that are readily observed to form in the local Universe today.
Item Description:Gesehen am 14.04.2023
Physical Description:Online Resource
ISSN:1365-2966
DOI:10.1093/mnras/stad044