On the origin of a rotating metal-poor stellar population in the Milky Way Nuclear Cluster

Abstract

We explore the origin of a population of stars recently detected in the inner parsec of the Milky Way Nuclear Cluster (NC), which exhibit sub-solar metallicity and a higher rotation compared to the dominant population. Using state-of-the-art $N$-body simulations, we model the infall of a massive stellar system into the Galactic center, both of Galactic and extra-galactic origin. We show that the newly discovered population can either be the remnant of a massive star cluster formed a few kpc away from the Galactic center (Galactic scenario) or be accreted from a dwarf galaxy originally located at 10-100 kpc (extragalactic scenario) and that reached the Galactic center 3-5 Gyr ago. A comparison between our models and characteristic Galactocentric distance and metallicity distributions of Milky Way satellites and globular clusters favours the Galactic scenario. A comparison with clusters associated with the Enceladus-Sausage, Sequoia, Sagittarius and Canis Major structures suggests that the progenitor of the observed metal-poor substructure formed in-situ rather than being accreted.

16 pages, 9 figures, 1 table, 2 online data files available upon publication. published in ApJL

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Cited by in corpus (31)

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• The Star Formation History of the Milky Way's Nuclear Star Cluster
• Formation of super-massive black holes in galactic nuclei I: delivering seed intermediate-mass black holes in massive stellar clusters
• Nuclear star cluster formation in star-forming dwarf galaxies
• Revealing the Formation of the Milky Way Nuclear Star Cluster via Chemo-Dynamical Modeling
• Disentangling the formation mechanisms of nuclear star clusters
• Formation of supermassive black holes in galactic nuclei II: retention and growth of seed intermediate-mass black holes
• Stellar Populations in the Transition Region of Nuclear Star Cluster and Nuclear Stellar Disc
• Constraints on the Galactic Centre environment from \textit{Gaia} hypervelocity stars III: Insights on a possible companion to Sgr A*
• Close stellar encounters at the Galactic Centre I: The effect on the observed stellar populations
• A numerical study of stellar discs in galactic nuclei
• PHANGS-JWST First Results: A combined HST and JWST analysis of the nuclear star cluster in NGC 628
• Measuring the Orbits of the Arches and Quintuplet Clusters using HST and Gaia: Exploring Scenarios for Star Formation Near the Galactic Center
• Smooth kinematic and metallicity gradients reveal that the Milky Way's nuclear star cluster and disc might be part of the same structure
• Are we observing a NSC in course of formation in the NGC 4654 galaxy?
• Milky Way globular clusters on cosmological timescales. II. Interaction with the Galactic centre
• MOCCA-Survey Database: Extra Galactic Globular Clusters. II. Milky Way and Andromeda
• Measuring the alpha-abundance of subsolar-metallicity stars in the Milky Way's central half-parsec: testing globular cluster and dwarf galaxy infall scenarios
• Tidal disruption of stellar clusters and their remnants' spatial distribution near the galactic center
• Dynamical mass distribution and velocity structure of the Galactic centre
• Growing a nuclear star cluster from star formation and cluster mergers: The JWST NIRSpec view of NGC 4654
• A Wide Metallicity Range for Gyr-old Stars in the Nuclear Star Cluster
• MOCCA-Survey Database: Extra Galactic Globular Clusters. III. The population of black holes in Milky Way and Andromeda-like galaxies
• Metallicity-dependent kinematics and orbits in the Milky Way's nuclear stellar disc
• Chemical analysis of the Milky Way's Nuclear Star Cluster: Evidence for a metallicity gradient
• Resonant Dynamical Friction in Nuclear Star Clusters: Rapid Alignment of an Intermediate-mass Black Hole with a Stellar Disk
• The Nuclear Star Cluster of M 74: a fossil record of the very early stages of a star-forming galaxy
• Resolved nuclear kinematics link the formation and growth of nuclear star clusters with the evolution of their early and late-type hosts
• Supergiant GCIRS 22 in the Milky Way Nuclear Star Cluster: Revised alpha abundances