The kinematics of globular cluster populations in the E-MOSAICS simulations and their implications for the assembly history of the Milky Way

Abstract

We present a detailed comparison of the Milky Way (MW) globular cluster (GC) kinematics with the 25 Milky Way-mass cosmological simulations from the E-MOSAICS project. While the MW falls within the kinematic distribution of GCs spanned by the simulations, the relative kinematics of its metal-rich ($[Fe/H]>-1.2$) versus metal-poor ($[Fe/H]<-1.2$), and inner ($r<8\mathrm{kpc}$) versus outer ($r>8\mathrm{kpc}$) populations are atypical for its mass. To understand the origins of these features, we perform a comprehensive statistical analysis of the simulations, and find 18 correlations describing the assembly of $L^{\ast }$ galaxies and their dark matter haloes based on their GC population kinematics. The correlations arise because the orbital distributions of accreted and in-situ GCs depend on the masses and accretion redshifts of accreted satellites, driven by the combined effects of dynamical fraction, tidal stripping, and dynamical heating. Because the kinematics of in-situ/accreted GCs are broadly traced by the metal-rich/metal-poor and inner/outer populations, the observed GC kinematics are a sensitive probe of galaxy assembly. We predict that relative to the population of $L^{\ast }$ galaxies, the MW assembled its dark matter and stellar mass rapidly through a combination of in-situ star formation, more than a dozen low-mass mergers, and $1.4\pm 1.2$ early ($z=3.1\pm 1.3$) major merger. The rapid assembly period ended early, limiting the fraction of accreted stars. We conclude by providing detailed quantitative predictions for the assembly history of the MW.

24 pages, 20 figures. Published in MNRAS

References in corpus (24)

• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe
• galpy: A Python Library for Galactic Dynamics
• The EAGLE simulations of galaxy formation: calibration of subgrid physics and model variations
• Chemical enrichment in cosmological, smoothed particle hydrodynamics simulations
• Evidence for Two Early Accretion Events That Built the Milky Way Stellar Halo
• The accretion origin of the Milky Way's stellar halo
• Tracing Galaxy Formation with Stellar Halos II: Relating Substructure in Phase- and Abundance-Space to Accretion Histories
• Streams, substructures and the early history of the Milky Way
• The ACS Virgo Cluster Survey XV. The Formation Efficiencies of Globular Clusters in Early-Type Galaxies: The Effects of Mass and Environment
• Kraken reveals itself -- the merger history of the Milky Way reconstructed with the E-MOSAICS simulations
• The stellar halo of the Galaxy
• A chronicle of galaxy mass assembly in the EAGLE simulation
• Reverse engineering the Milky Way
• ZFOURGE/CANDELS: On the Evolution of M* Galaxy Progenitors from z=3 to 0.5
• The total stellar halo mass of the Milky Way
• The E-MOSAICS project: tracing galaxy formation and assembly with the age-metallicity distribution of globular clusters
• Halo Substructure in the SDSS-Gaia Catalogue : Streams and Clumps
• Formation histories of stars, clusters and globular clusters in the E-MOSAICS simulations
• The Next Generation Virgo cluster Survey. V. modelling the dynamics of M87 with the Made-to-Measure method
• Predicting accreted satellite galaxy masses and accretion redshifts based on globular cluster orbits in the E-MOSAICS simulations
• Where did the globular clusters of the Milky Way form? Insights from the E-MOSAICS simulations
• The [α/Fe]-[Fe/H] relation in the E-MOSAICS simulations: its connection to the birth place of globular clusters and the fraction of globular cluster field stars in the bulge
• On the Mass Assembly History of the Local Group

Cited by in corpus (22)

• Star clusters near and far; tracing star formation across cosmic time
• The Chemo-Dynamical Groups of Galactic Globular Clusters
• The Sparkler: Evolved High-Redshift Globular Clusters Captured by JWST
• Introducing EMP-Pathfinder: modelling the simultaneous formation and evolution of stellar clusters in their host galaxies
• Predicting accreted satellite galaxy masses and accretion redshifts based on globular cluster orbits in the E-MOSAICS simulations
• Globular clusters as tracers of the dark matter halo: insights from the E-MOSAICS simulations
• Globular cluster formation histories, masses and radii inferred from gravitational waves
• Modeling the kinematics of globular cluster systems
• What Are Those Tiny Things? A First Study of Compact Star Clusters in the SMACS0723 Field with JWST
• Relative Ages of Nine Inner Milky Way Globular Clusters from Proper Motion Cleaned Color-Magnitude Diagrams
• Modeling globular clusters in the TNG50 simulation: predictions from dwarfs to giants
• The Age-Metallicity-Specific Orbital Energy Relation for the Milky Way's Globular Cluster System Confirms the Importance of Accretion for Its Formation
• Catalogue of model star clusters in the Milky Way and M31 galaxies
• Tidal disruption of star clusters in galaxy formation simulations
• Peeking beneath the precision floor -- II. Probing the chemo-dynamical histories of the potential globular cluster siblings, NGC 288 and NGC 362
• The physics governing the upper truncation mass of the globular cluster mass function
• What to expect when using globular clusters as tracers of the total mass distribution in Milky Way-mass galaxies
• The Next Generation Virgo Cluster Survey. XXXIII. Stellar Population Gradients in the Virgo Cluster Core Globular Cluster System
• The formation and disruption of globular cluster populations in simulations of present-day $L^{\ast }$ galaxies with controlled assembly histories
• Study of the Influence of an Evolving Galactic Potential on the Orbital Properties of 152 Globular clusters with Data from the Gaia EDR3 Catalogue
• The present-day globular cluster kinematics of lenticular galaxies from the E-MOSAICS simulations and their relation to the galaxy assembly histories
• Massive Star Clusters in the Semi-Analytical Galaxy Formation Model L-Galaxies 2020