Nuclear star clusters as probes of dark matter halos: the case of the Sagittarius Dwarf Spheroidal Galaxy

Abstract

The Sagittarius dwarf spheroidal (Sgr dSph) galaxy is currently being accreted and disrupted by the tidal field of the Milky Way. Recent observations have shown that the central region of the dwarf hosts at least three different stellar populations, ranging from old and metal-poor over intermediate metal-rich to young metal-rich. While the intermediate-age metal-rich population has been identified as part of the galaxy, the oldest and youngest populations belong to M54, the nuclear star cluster (NSC) of the Sgr dSph galaxy. The old metal-poor component of M54 has been interpreted as at least one decayed GC which was initially orbiting its host galaxy. The youngest population formed in situ from gas accreted into M54 after its arrival at the centre of the host. In this work, we use the observed properties of M54 to explore the shape of the inner density profile of the Sgr dSph galaxy. To do so, we simulate the decay of M54 towards the centre of the dark matter (DM) halo of its host. We model the DM density profile using different central slopes, and we compare the results of the simulations to the most recent observations of the structural properties of M54. From this comparison, we conclude that a GC that decays in a DM halo with a density profile $\propto r^{-\gamma }$ and $\gamma \le 1$ shows a rotational signal and flattening comparable to those observed for M54. Steeper profiles produce, instead, highly rotating and more flattened NSCs which do not match the properties of M54.

11 pages, 4 figures, 1 table. Accepted for publication in MNRAS

References in corpus (33)

• High-resolution mass models of dwarf galaxies from LITTLE THINGS
• Nuclear Star Clusters
• The kinematic status and mass content of the Sculptor dwarf spheroidal galaxy
• A mass-dependent density profile for dark matter haloes including the influence of galaxy formation
• Axion dark matter, solitons, and the cusp-core problem
• Does the Fornax dwarf spheroidal have a central cusp or core?
• Dwarf galaxies in CDM and SIDM with baryons: observational probes of the nature of dark matter
• The nucleus of the Sagittarius dSph galaxy and M54: a window on the process of galaxy nucleation
• Dynamical friction in constant density cores: a failure of the Chandrasekhar formula
• Dwarf Galaxy Dark Matter Density Profiles Inferred from Stellar and Gas Kinematics
• The core-cusp problem: a matter of perspective
• Self-consistent simulations of Nuclear Cluster formation through Globular Cluster orbital decay and merging
• The global mass functions of 35 Galactic globular clusters: I. Observational data and correlations with cluster parameters
• Henize 2-10: the ongoing formation of a nuclear star cluster around a massive black hole
• Chemical abundances in the nucleus of the Sagittarius dwarf spheroidal galaxy
• On the rotation of nuclear star clusters formed by cluster-inspirals
• A semi-analytic dynamical friction model for cored galaxies
• A deep view into the nucleus of the Sagittarius Dwarf Spheroidal Galaxy with MUSE. I. Data and stellar population characterization
• Predicted Extension of the Sagittarius Stream to the Milky Way Virial Radius
• 3D motions in the Sculptor dwarf galaxy as a glimpse of a new era
• The nucleation fraction of Local Volume galaxies
• Self-Regulated Fueling of Galaxy Centers: Evidence for Star-Formation Feedback in IC342's Nucleus
• A Hybrid N-Body Code Incorporating Algorithmic Regularization and Post-Newtonian Forces
• Gas dynamics in dwarf galaxies as testbeds for dark matter and galaxy evolution
• Deadly dark matter cusps vs faint and extended star clusters: Eridanus II and Andromeda XXV
• The Dark Matter Distributions in Low-Mass Disk Galaxies. II. The Inner Density Profiles
• A deep view into the nucleus of the Sagittarius Dwarf Spheroidal Galaxy with MUSE. II. Kinematic characterization of the stellar populations
• Lack of nuclear clusters in dwarf spheroidal galaxies: implications for massive black holes formation and the cusp/core problem
• Cusp or core? Revisiting the globular cluster timing problem in Fornax
• Probing the formation history of the nuclear star cluster at the Galactic Centre with millisecond pulsars
• Discovery of new globular clusters in the Sagittarius dwarf galaxy
• Globular clusters as tracers of the host galaxy mass distribution: the Fornax dSph test case
• The Dark Matter Distributions in Low-Mass Disk Galaxies. I. H$\alpha$ Observations Using the Palomar Cosmic Web Imager

Cited by in corpus (1)

• The Pristine Inner Galaxy Survey (PIGS) X. Probing the early chemical evolution of the Sagittarius dwarf galaxy with carbon abundances