Formation and evolution of nuclear star clusters with in-situ star-formation: Nuclear cores and age segregation

Abstract

Nuclear stellar cluster (NSCs) are known to exist around massive black holes (MBHs) in galactic nuclei. Two formation scenarios were suggested for their origin: (1) Build-up of NSCs from consecutive infall of stellar cluster and (2) Continuous in-situ star-formation. Though the cluster-infall scenario has been extensively studied in recent years, the in-situ formation scenario have been hardly explored. Here we use Fokker-Planck (FP) calculations to study the effects of star formation on the build-up of NSCs and its implications for their long term evolution and their resulting structure. We use the FP equation to describe the evolution of several stellar populations, and add appropriate source terms to account for the effects of newly formed stars. We show that continuous star-formation even 1-2 pc away from the MBH can lead to the build-up of an NSC with properties similar to those of the Milky-way NSC. We also find that the general structure of the old stellar population in the NSC with in-situ star-formation could be very similar to the steady-state Bahcall-Wolf cuspy structure. However, its younger stellar population do not yet achieve a steady state. In particular, formed/evolved NSCs with in-situ star-formation contain differential age-segregated stellar populations which are not yet fully mixed. Younger stellar populations formed in the outer regions of the NSC have a cuspy structure towards the NSC outskirts, while showing a core-like distribution inwards; with younger populations having larger core sizes. In principal, such a structure can give rise to an apparent core-like radial distribution of younger (up to 2-3 Gyrs) stars, as observed in the Galactic center. Such an NSC still preserves an underlying stellar cusp of older stars, that can be potentially be missed by current observations of red-giants.

arXiv commentComments are welcome, Accepted for publication in ApJ

References in corpus (40)

• A Fundamental Relation Between Supermassive Black Holes and Their Host Galaxies
• The Galactic Center Massive Black Hole and Nuclear Star Cluster
• The ACS Virgo Cluster Survey. VI. Isophotal Analysis and the Structure of Early-Type Galaxies
• Stellar disk in the galactic center -- a remnant of a dense accretion disk?
• Resonant Relaxation in Stellar Systems
• An Extremely Top-Heavy IMF in the Galactic Center Stellar Disks
• A Disk of Young Stars at the Galactic Center as Determined by Individual Stellar Orbits
• Evidence for Warped Disks of Young Stars in the Galactic Center
• Massive perturber-driven interactions of stars with a massive black hole
• Masses of star clusters in the nuclei of bulge-less spiral galaxies
• The effect of mass-segregation on gravitational wave sources near massive black holes
• Resonant relaxation near a massive black hole: the stellar distribution and gravitational wave sources
• Stellar remnants in galactic nuclei: mass segregation
• Strong mass segregation around a massive black hole
• Dissipationless Formation and Evolution of the Milky Way Nuclear Star Cluster
• An Extended Star Formation History for the Galactic Center from Hubble Space Telescope/NICMOS Observations
• Nuclear star clusters in 228 spiral galaxies in the HST/WFPC2 archive: catalogue and comparison to other stellar systems
• High angular resolution integral-field spectroscopy of the Galaxy's nuclear cluster: a missing stellar cusp?
• Clues to Nuclear Star Cluster Formation from Edge-on Spirals
• The star formation history of the Milky Way's Nuclear Star Cluster
• The Distribution of Stars and Stellar Remnants at the Galactic Center
• Origin and growth of nuclear star clusters around massive black holes
• Sgr A* Companion S0-2: A Probe of Very High-Mass Star Formation
• The Evolution of the Globular Cluster System in a Triaxial Galaxy: Can a Galactic Nucleus Form by Globular Cluster Capture?
• Evidence for a Long-Standing Top-Heavy IMF in the Central Parsec of the Galaxy
• The distribution of stars near the super-massive black hole in the Galactic Center
• Simulations of the formation of stellar discs in the Galactic centre via cloud-cloud collisions
• Dynamical evolution of the young stars in the Galactic center: N-body simulations of the S-stars
• Red giant stellar collisions in the Galactic Centre
• N-Body Growth of a Bahcall-Wolf Cusp Around a Black Hole
• The M-sigma Relation for Nucleated Galaxies
• 3D stellar kinematics at the Galactic center: measuring the nuclear star cluster spatial density profile, black hole mass, and distance
• Nuclear Star Clusters from Clustered Star Formation
• Red giant collisions in the galactic centre
• Age and mass segregation of multiple stellar populations in galactic nuclei and their observational signatures
• Dynamical constraints on the origin of the young B-stars in the Galactic center
• The fragmenting past of the disk at the Galactic Center : The culprit for the missing red giants
• Eccentric disc instability in stellar discs formed from inspiraling gas clouds in the Galactic Centre
• Probing the formation of planetesimals in the Galactic Centre using Sgr A* flares
• The Impact of Stellar Collisions in the Galactic Center

Cited by in corpus (43)

• Nuclear Star Clusters
• Black hole and neutron star mergers in galactic nuclei
• Co-evolution of nuclear star clusters, massive black holes and their host galaxies
• The impact of vector resonant relaxation on the evolution of binaries near a massive black hole: implications for gravitational wave sources
• An Overabundance of Black Hole X-Ray Binaries in the Galactic Center from Tidal Captures
• The Milky Way's nuclear star cluster: Old, metal-rich, and cuspy
• The distribution of old stars around the Milky Way's central black hole I: Star counts
• KMOS view of the Galactic Centre - II. Metallicity distribution of late-type stars
• The distribution of stars around the Milky Way's black hole III: Comparison with simulations
• Henize 2-10: the ongoing formation of a nuclear star cluster around a massive black hole
• A new Fokker-Planck approach for relaxation-driven evolution of galactic nuclei
• The imprint of massive black-hole mergers on the correlation between nuclear clusters and their host galaxies
• The distribution of stars around the Milky Way's central black hole II: Diffuse light from sub-giants and dwarfs
• The impact of mass segregation and star-formation on the rates of gravitational-wave sources from extreme mass ratio inspirals
• Steeper stellar cusps in galactic centers from binary disruption
• Asymmetric spatial distribution of sub-solar metallicity stars in the Milky Way nuclear star cluster
• Formation of super-massive black holes in galactic nuclei I: delivering seed intermediate-mass black holes in massive stellar clusters
• Gamma-ray and X-ray emission from the Galactic Centre: hints on the nuclear star cluster formation history
• Lack of nuclear clusters in dwarf spheroidal galaxies: implications for massive black holes formation and the cusp/core problem
• Capture of stars into gaseous discs around massive black holes: Alignment, circularization and growth
• The Galactic Center as a laboratory for theories of gravity and dark matter
• Massive binary star mergers in galactic nuclei: implications for blue stragglers, binary S-stars and gravitational waves
• Probing the formation history of the nuclear star cluster at the Galactic Centre with millisecond pulsars
• Supernova Kicks and Dynamics of Compact Remnants in the Galactic Centre
• The MEGaN project I. Missing formation of massive nuclear clusters and tidal disruption events by star clusters - massive black hole interactions
• Dark matter concentrations in galactic nuclei according to polytropic models
• Gravitational-wave captures by intermediate-mass black holes in galactic nuclei
• A population of compact radio variables and transients in the radio bright zone at the Galactic center observed with the Jansky Very Large Array
• Formation of supermassive black holes in galactic nuclei II: retention and growth of seed intermediate-mass black holes
• Star formation at the Galactic Centre: coevolution of multiple young stellar discs
• Efficiency of black hole formation via collisions in stellar systems: An analysis of data from simulations and observations
• The Origin of Stars in the Inner 500 Parsecs in TNG50 Galaxies
• Observational signatures of the black hole Mass Distribution in the Galactic Center
• The History of Tidal Disruption Events in Galactic Nuclei
• Demographics of Tidal Disruption Events with L-Galaxies: I. Volumetric TDE rates and the abundance of Nuclear Star Clusters
• Smooth kinematic and metallicity gradients reveal that the Milky Way's nuclear star cluster and disc might be part of the same structure
• Growing a nuclear star cluster from star formation and cluster mergers: The JWST NIRSpec view of NGC 4654
• Relativistic scattering of a fast spinning neutron star by a massive black hole
• The S stars' zone of avoidance in the Galactic center
• Short and long term evolution of a stellar disk around a massive black hole: The role of binaries, the cusp and stellar evolution
• Supernovae in massive binaries and compact object mergers near supermassive black holes
• Chemical analysis of the Milky Way's Nuclear Star Cluster: Evidence for a metallicity gradient
• Could globular clusters in the vicinity of the galactic centre have contributed stars to the nuclear star cluster in the past?