The distribution of globular clusters in kinematic spaces does not trace the accretion history of the host galaxy

Abstract

Reconstructing how all the stellar components of the Galaxy formed and assembled over time, by studying the properties of the stars which make it, is the aim of Galactic archeology. In these last years, thanks to the launch of the ESA Gaia astrometric mission, and the development of many spectroscopic surveys, we are for the first time in the position to delve into the layers of the past of our galaxy. Globular clusters (GCs) play a fundamental role in this research field since they are among the oldest stellar systems in the Milky Way (MW) and so bear witness of its entire past. In the recent years, there have been several attempts to constrain the nature of clusters (accreted or formed in the MW itself) through the analysis of kinematic spaces and to reconstruct from this the properties of the accretions events experienced by the MW through time. This work aims to test a widely-used assumption about the clustering of the accreted populations of GCs in the integrals of motions space. We analyze a set of dissipation-less N-body simulations that reproduce the accretion of one or two satellites with their GC population on a MW-type galaxy. Our results demonstrate that a significant overlap between accreted and "kinematically-heated" in-situ GCs is expected in kinematic spaces, for mergers with mass ratios of 1:10. In contrast with standard assumptions made in the literature so far, we find that accreted GCs do not show dynamical coherence, that is they do not cluster in kinematic spaces. In addition, GCs can also be found in regions dominated by stars which have a different origin (i.e. different progenitor). This casts doubt on the association between GCs and field stars that is generally made in the literature to assign them to a common origin. Our findings severely question the recovered accretion history of the MW based on the phase-space clustering of the GC population.

arXiv commentAccepted for publication on A&A. Major additions implemented to the first version

References in corpus (95)

• Gaia Data Release 2. Summary of the contents and survey properties
• The merger that led to the formation of the Milky Way's inner stellar halo and thick disk
• A 2MASS All-Sky View of the Sagittarius Dwarf Galaxy: I. Morphology of the Sagittarius Core and Tidal Arms
• Co-formation of the Galactic disc and the stellar halo
• Observational and Theoretical Constraints on Singular Dark Matter Halos
• The Ghost of Sagittarius and Lumps in the Halo of the Milky Way
• Gaia Data Release 2: Kinematics of globular clusters and dwarf galaxies around the Milky Way
• Debris streams in the solar neighbourhood as relicts from the formation of the Milky Way
• AGAMA: Action-based galaxy modelling architecture
• Two distinct halo populations in the solar neighborhood. Evidence from stellar abundance ratios and kinematics
• A catalogue of masses, structural parameters and velocity dispersion profiles of 112 Milky Way globular clusters
• Mass Density Profiles of LSB Galaxies
• The age structure of stellar populations in the solar vicinity. Clues of a two-phase formation history of the Milky Way disk
• Properties of stellar generations in Globular Clusters and relations with global parameters
• Evidence for Two Early Accretion Events That Built the Milky Way Stellar Halo
• The ACS Survey of Galactic Globular Clusters. VII. Relative Ages
• The Ages of 55 Globular Clusters as Determined Using an Improved delta V_TO^HB Method Along with Color-Magnitude Diagram Constraints, and Their Implications for Broader Issues
• The ACS Survey of Galactic Globular Clusters. IX. Horizontal Branch Morphology and the Second Parameter Phenomenon
• Quantifying the Fragility of Galactic Disks in Minor Mergers
• Mean proper motions, space orbits and velocity dispersion profiles of Galactic globular clusters derived from Gaia DR2 data
• Origin of the system of globular clusters in the Milky Way
• Internal Dynamics of Globular Clusters
• Evidence from the H3 Survey that the Stellar Halo is Entirely Comprised of Substructure
• Accurate distances to Galactic globular clusters through a combination of Gaia EDR3, HST and literature data
• Our Milky Way as a Pure-Disk Galaxy -- A Challenge for Galaxy Formation
• The formation and assembly history of the Milky Way revealed by its globular cluster population
• In disguise or out of reach: first clues about in-situ and accreted stars in the stellar halo of the Milky Way from Gaia DR2
• The Dual Origin of Stellar Halos
• Mass Models for Low Surface Brightness Galaxies with High Resolution Optical Velocity Fields
• A Catalog of Globular Cluster Systems: What Determines the Size of a Galaxy's Globular Cluster Population?
• The ACS Survey of Galactic Globular Clusters. II. Stellar Evolution Tracks, Isochrones, Luminosity Functions, and Synthetic Horizontal-Branch Models
• The Milky Way stellar halo out to 40 kpc : Squashed, broken but smooth
• Proper motions and dynamics of the Milky Way globular cluster system from Gaia DR2
• Thin, thick and dark discs in LCDM
• The origin of accreted stellar halo populations in the Milky Way using APOGEE, $\text{Gaia}$, and the EAGLE simulations
• Actions for axisymmetric potentials
• What is a globular cluster? An observational perspective
• Kraken reveals itself -- the merger history of the Milky Way reconstructed with the E-MOSAICS simulations
• Merger Histories of Galaxy Halos and Implications for Disk Survival
• The Bulge Radial Velocity Assay (BRAVA): II. Complete Sample and Data Release
• The Bifurcated Age-Metallicity Relation of Milky Way Globular Clusters and its Implications For the Accretion History of the Galaxy
• Mapping the substructure in the Galactic halo with the next generation of astrometric satellites
• The Milky Way has no in-situ halo other than the heated thick disc. Composition of the stellar halo and age-dating the last significant merger with Gaia DR2 and APOGEE
• The Galaxy and its stellar halo: insights on their formation from a hybrid cosmological approach
• From dawn till disk: Milky Way's turbulent youth revealed by the APOGEE+Gaia data
• Contributions to the accreted stellar halo: an atlas of stellar deposition
• The Global Dynamical Atlas of the Milky Way mergers: Constraints from Gaia EDR3 based orbits of globular clusters, stellar streams and satellite galaxies
• Reverse engineering the Milky Way
• APOGEE: The Apache Point Observatory Galactic Evolution Experiment
• The dominant epoch of star formation in the Milky Way formed the thick disc
• Global structure and kinematics of stellar haloes in cosmological hydrodynamic simulations
• The dwarf galaxy DDO 47 as a dark matter laboratory: testing cusps hiding in triaxial halos
• Formation of In Situ Stellar Haloes in Milky Way-Mass Galaxies
• The total stellar halo mass of the Milky Way
• Halpha rotation curves: the soft core question
• Discovery of a New, Polar-Orbiting Debris Stream in the Milky Way Stellar Halo
• Characterization and history of the Helmi streams with Gaia DR2
• Evolution of star clusters in arbitrary tidal fields
• The origin of the Milky Way globular clusters
• All-Sky Dynamical Response of the Galactic Halo to the Large Magellanic Cloud
• The fine-grained phase-space structure of Cold Dark Matter halos
• The Milky Way Halo in Action Space
• On the kinematic detection of accreted streams in the Gaia era: a cautionary tale
• The Eating Habits of Milky Way Mass Halos: Destroyed Dwarf Satellites and the Metallicity Distribution of Accreted Stars
• Formation and evolution of galactic disks with a multiphase numerical model
• The X-shaped Bulge of the Milky Way revealed by WISE
• Halo Star Streams in the Solar Neighborhood
• The Chemical Compositions of Accreted and {\it in situ} Galactic Globular Clusters According to SDSS/APOGEE
• The Chemo-Dynamical Groups of Galactic Globular Clusters
• Detection of the LMC-induced sloshing of the Galactic halo
• A Low-Mass Stellar-Debris Stream Associated with a Globular Cluster Pair in the Halo
• Characteristics of thick disks formed through minor mergers: stellar excesses and scale lengths
• VINTERGATAN II: the history of the Milky Way told by its mergers
• Chaotic Dispersal of Tidal Debris
• An Iterative Method for Constructing Equilibrium Phase Models of Stellar Systems
• Why the Milky Way's bulge is not only a bar formed from a cold thin disk
• GASTRO library I: the simulated chemodynamical properties of several GSE-like stellar halos
• A massive mess: When a large dwarf and a Milky Way-like galaxy merge
• Tidal disruption of globular clusters in dwarf galaxies with triaxial dark matter haloes
• The disc origin of the Milky Way bulge
• The effects of dynamical substructure on Milky Way mass estimates from the high velocity tail of the local stellar halo
• Exploring the Galaxy's halo and very metal-weak thick disk with SkyMapper and Gaia DR2
• The formation of a thick disk through the heating of a thin disk: Agreement with orbital eccentricities of stars in the solar neighborhood
• Radialization of satellite orbits in galaxy mergers
• The Kinematic Properties of Milky Way Stellar Halo Populations
• The Galaxy Progenitors of Stellar Streams around Milky Way-mass Galaxies in the FIRE Cosmological Simulations
• Predicting accreted satellite galaxy masses and accretion redshifts based on globular cluster orbits in the E-MOSAICS simulations
• A Swing of the Pendulum: The Chemodynamics of the Local Stellar Halo Indicate Contributions from Several Radial Merger Events
• A flexible method to evolve collisional systems and their tidal debris in external potentials
• Modeling the kinematics of globular cluster systems
• The Effects of Dwarf Galaxies on the Orbital Evolution of Galactic Globular Clusters
• Simulating cosmological substructure in the solar neighbourhood
• The accretion history of the Milky Way. I. How it shapes globular clusters and dwarf galaxies
• Searching for a kinematic signature of the moderately metal-poor stars in the Milky Way bulge using N-body simulations
• Concurrent infall of satellites: Collective effects changing the overall picture

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• Galactic Archaeology with Gaia
• The stellar halo in Local Group Hestia simulations I. The in-situ component and the effect of mergers
• Metallicity distributions of halo stars: do they trace the Galactic accretion history?
• Milky Way globular clusters on cosmological timescales. I. Evolution of the orbital parameters in time-varying potentials
• The stellar halo in Local Group Hestia simulations II. The accreted component
• The stellar halo in Local Group Hestia simulations III. Chemical abundance relations for accreted and in-situ stars
• Chronology of the chemical enrichment of the old Galactic stellar populations
• A portrait of the Vast Polar Structure as a young phenomenon: hints from its member satellites
• Gravitational waves from mergers of Population III binary black holes: roles played by two evolution channels
• Exploring the chemodynamics of metal-poor stellar populations
• Abundance ties: Nephele and the globular cluster population accreted with $\omega$ Cen. Based on APOGEE DR17 and Gaia EDR3
• Galaxy archaeology for wet mergers: Globular cluster age distributions in the Milky Way and nearby galaxies
• Evidence of Gaia Enceladus experiencing at least two passages around the Milky Way
• How well can we unravel the accreted constituents of the Milky Way stellar halo? A test on cosmological hydrodynamical simulations
• The Influence of the Galactic Bar on the Dynamics of Globular Clusters
• Rediscovering the Milky Way with orbit superposition approach and APOGEE data I. Method validation
• Chronology of our Galaxy from Gaia colour-magnitude diagram fitting (ChronoGal) -- III. Age and metallicity distribution of Gaia-Sausage-Enceladus stars near the Sun
• The Milky Way accretion history compared to cosmological simulations -- from bulge to dwarf galaxy infall
• Globular clusters in \textsc{OrbIT}: complete dynamical characterisation of the globular cluster population of the Milky Way through updated orbital reconstruction
• CAPOS: The bulge Cluster APOgee Survey VIII. Final ASPCAP results for all clusters
• On the Use of Field RR Lyrae as Galactic Probes -- VIII. Early Formation of the Galactic Spheroid
• Rediscovering the Milky Way with orbit superposition approach and APOGEE data III. Panoramic view of the bulge
• Main-sequence Turnoff Stars as Probes of the Ancient Galactic Relic: Chemo-dynamical Analysis of a Pilot Sample
• The Nephele ecosystem: stars, globular clusters, and stellar streams associated with the progenitor galaxy of $\omega$ Centauri
• Investigating the origin of the Milky Way streams. A revised look at their orbital pole distribution in light of precession effects