The origin of the Milky Way globular clusters

Research output: Contribution to journalArticle

Abstract

We present a cosmological zoom-in simulation of a Milky Way-like galaxy used to explore the formation and evolution of star clusters. We investigate in particular the origin of the bimodality observed in the colour and metallicity of globular clusters, and the environmental evolution through cosmic times in the form of tidal tensors. Our results self-consistently confirm previous findings that the blue, metal-poor clusters form in satellite galaxies that are accreted on to the Milky Way, while the red, metal-rich clusters form mostly in situ, or, to a lower extent, in massive, self-enriched galaxies merging with the Milky Way. By monitoring the tidal fields these populations experience, we find that clusters formed in situ (generally centrally concentrated) feel significantly stronger tides than the accreted ones, both in the present day, and when averaged over their entire life. Furthermore, we note that the tidal field experienced by Milky Way clusters is significantly weaker in the past than at present day, confirming that it is unlikely that a power-law cluster initial mass function like that of young massive clusters, is transformed into the observed peaked distribution in the Milky Way with relaxation-driven evaporation in a tidal field.

Details

Authors
Organisations
External organisations
  • University of Surrey
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Astronomy, Astrophysics and Cosmology

Keywords

  • Galaxies: formation, Galaxies: star clusters: general, Methods: numerical
Original languageEnglish
Pages (from-to)3622-3636
Number of pages15
JournalMonthly Notices of the Royal Astronomical Society
Volume465
Issue number3
Publication statusPublished - 2017 Jan 1
Publication categoryResearch
Peer-reviewedYes