Tidal disruption of stellar clusters and their remnants' spatial distribution near the galactic center

Abstract

The accretion of massive star clusters via dynamical friction has previously been established to be a likely scenario for the build up of nuclear stellar clusters (NSCs). A remaining issue is whether strong external tidal perturbation may lead to the severe disruption of loosely-bound clusters well before they sink deeply into the center of their host galaxies. We carry out a series of $N$-body simulations and verify our early idealized analytic models. We show if the density profile of the host galaxies can be described by a power-law distribution with an index, $\alpha <1$, the cluster would be compressed in the radial direction by the external galactic tidal field. In contrast, the galactic tidal perturbation is disruptive in regions with a steep, $\alpha >1$, density fall-off or in the very center where gravity is dominated by the point-mass potential of super-massive black holes (SMBHs). This sufficient criterion supplements the conventional necessary Roche-lobe-filling condition in determining the preservation versus disintegration of satellite stellar systems. We simulate the disruption of stellar clusters which venture on nearly-circular, modestly- or highly-eccentric orbits into the center of galaxies with a range of background density profiles and SMBHs. We obtain the spatial distribution of the stellar-cluster remnants. We apply these results to the NSC within a few parsecs from SMBH Sgr A${}^{\ast }$ at the Galactic Center. Recent observations indicate the coexistence of two populations of stars with distinctively separate ages and metallicities. We verify that the subsolar-metalicity population can be the debris of disrupted stellar clusters.

21 pages, 18 figures, accepted for publication in ApJ

References in corpus (20)

• galpy: A Python Library for Galactic Dynamics
• An Update on Monitoring Stellar Orbits in the Galactic Center
• Accurate distances to Galactic globular clusters through a combination of Gaia EDR3, HST and literature data
• The dynamical evolution of molecular clouds near the Galactic Centre - I. Orbital structure and evolutionary timeline
• Large scale kinematics and dynamical modelling of the Milky Way nuclear star cluster
• PeTar: a high-performance N-body code for modeling massive collisional stellar systems
• Halo Substructure in the SDSS-Gaia Catalogue : Streams and Clumps
• The Globular Cluster Migratory Origin of Nuclear Star Clusters
• Self-consistent simulations of Nuclear Cluster formation through Globular Cluster orbital decay and merging
• Henize 2-10: the ongoing formation of a nuclear star cluster around a massive black hole
• On the rotation of nuclear star clusters formed by cluster-inspirals
• A slow-down time-transformed symplectic integrator for solving the few-body problem
• Metal-poor nuclear star clusters in two dwarf galaxies near Centaurus A suggesting formation from the in-spiraling of globular clusters
• On the origin of a rotating metal-poor stellar population in the Milky Way Nuclear Cluster
• The Influence of Mass-Loss from a Star Cluster on its Dynamical Friction -- I. Clusters without Internal Evolution
• Lack of nuclear clusters in dwarf spheroidal galaxies: implications for massive black holes formation and the cusp/core problem
• Revealing the Formation of the Milky Way Nuclear Star Cluster via Chemo-Dynamical Modeling
• The MEGaN project I. Missing formation of massive nuclear clusters and tidal disruption events by star clusters - massive black hole interactions
• The secular evolution of a uniform density star cluster immersed in a compressible galactic tidal field
• Exact equilibria of a stellar system in a linearised tidal field

Cited by in corpus (3)

• Gravitational waves from mergers of Population III binary black holes: roles played by two evolution channels
• Milky Way globular clusters on cosmological timescales. II. Interaction with the Galactic centre
• Dynamics of star associations in an SMBH-IMBH system: The case of IRS13 in the Galactic centre