The nuclear star cluster of the Milky Way: proper motions and mass

Abstract

Nuclear star clusters (NSCs) are located at the photometric and dynamical centers of the majority of galaxies. They are among the densest star clusters in the Universe. The NSC in the Milky Way is the only object of this class that can be resolved into individual stars. We measured the proper motions of more than 6000 stars within ~1.0 pc of the supermassive black hole Sgr A*. The full data set is provided in this work. We largely exclude the known early-type stars with their peculiar dynamical properties from the dynamical analysis. The cluster is found to rotate parallel to Galactic rotation, while the velocity dispersion appears isotropic (or anisotropy may be masked by the cluster rotation). The Keplerian fall-off of the velocity dispersion due to the point mass of Sgr A* is clearly detectable only at R <~ 0.3 pc. Nonparametric isotropic and anisotropic Jeans models are applied to the data. They imply a best-fit black hole mass of 3.6 (+0.2/-0.4) x 10^6 solar masses. Although this value is slightly lower than the current canonical value of 4.0x10^6 solar masses, this is the first time that a proper motion analysis provides a mass for Sagittarius A* that is consistent with the mass inferred from orbits of individual stars. The point mass of Sagittarius A* is not sufficient to explain the velocity data. In addition to the black hole, the models require the presence of an extended mass of 0.5-1.5x10^6 solar masses in the central parsec. This is the first time that the extended mass of the nuclear star cluster is unambiguously detected. The influence of the extended mass on the gravitational potential becomes notable at distances >~0.4 pc from Sgr A*. Constraints on the distribution of this extended mass are weak. The extended mass can be explained well by the mass of the stars that make up the cluster.

accepted for publication in Astronomy & Astrophysics; please contact first author for higher quality figures

References in corpus (17)

• Monitoring stellar orbits around the Massive Black Hole in the Galactic Center
• Measuring Distance and Properties of the Milky Way's Central Supermassive Black Hole with Stellar Orbits
• The Two Young Star Disks in the Central Parsec of the Galaxy: Properties, Dynamics and Formation
• The ACS Virgo Cluster Survey. VIII. The Nuclei of Early-Type Galaxies
• A Fundamental Relation Between Compact Stellar Nuclei, Supermassive Black Holes, and Their Host Galaxies
• The structure of the nuclear stellar cluster of the Milky Way
• The Coincidence of Nuclear Star Clusters and Active Galactic Nuclei
• Stellar populations in the nuclei of late-type spiral galaxies
• From Supermassive Black Holes to Dwarf Elliptical Nuclei: a Mass Continuum
• Kinematics of the old stellar population at the Galactic Center
• Evidence for a Long-Standing Top-Heavy IMF in the Central Parsec of the Galaxy
• The distance to the Galactic Centre based on Population-II Cepheids and RR Lyrae stars
• The Position of Sagittarius A*: III. Motion of the Stellar Cusp
• The K-band Spectrum of The Hot Star in IRS~8: An Outsider in the Galactic Center?
• Radial Velocities of Stars in the Galactic Center
• Composition of the galactic center star cluster
• Dynamics of galactic nuclei: Mass segregation and collisions

Cited by in corpus (191)

• Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies
• The Galactic Center Massive Black Hole and Nuclear Star Cluster
• Detection of the gravitational redshift in the orbit of the star S2 near the Galactic centre massive black hole
• Can environmental effects spoil precision gravitational-wave astrophysics?
• Detection of the Schwarzschild precession in the orbit of the star S2 near the Galactic centre massive black hole
• Secular evolution of compact binaries near massive black holes: gravitational wave sources and other exotica
• Intermediate mass black holes in AGN disks: I. Production & Growth
• A Supermassive Black Hole in an Ultracompact Dwarf Galaxy
• Testing General Relativity with stellar orbits around the supermassive black hole in our Galactic center
• Galactic Searches for Dark Matter
• Improving Galactic Center Astrometry by Reducing the Effects of Geometric Distortion
• Surface Brightness Profile of the Milky Way's Nuclear Star Cluster
• The old nuclear star cluster in the Milky Way: dynamics, mass, statistical parallax, and black hole mass
• Dissipationless Formation and Evolution of the Milky Way Nuclear Star Cluster
• Testing Properties of the Galactic Center Black Hole Using Stellar Orbits
• Properties of the Remnant Clockwise Disk of Young Stars in the Galactic Center
• Fast coalescence of massive black hole binaries from mergers of galactic nuclei: implications for low-frequency gravitational-wave astrophysics
• The star formation history of the Milky Way's Nuclear Star Cluster
• Spectral Models for Low-luminosity Active Galactic Nuclei in LINERs: The Role of Advection-dominated Accretion and Jets
• The Distribution of Stars and Stellar Remnants at the Galactic Center
• Origin and growth of nuclear star clusters around massive black holes
• A Maximum Stellar Surface Density in Dense Stellar Systems
• Large scale kinematics and dynamical modelling of the Milky Way nuclear star cluster
• Resonant relaxation and the warp of the stellar disc in the Galactic centre
• Stellar Evolution in AGN Disks
• Nearby Early-Type Galactic Nuclei at High Resolution: Dynamical Black Hole and Nuclear Star Cluster Mass Measurements
• Sgr A* and General Relativity
• On strong mass segregation around a massive black hole: Implications for lower-frequency gravitational-wave astrophysics
• A strongly magnetized pulsar within grasp of the Milky Way's supermassive black hole
• The HST/ACS Coma Cluster Survey. X. Nuclear star clusters in low-mass early-type galaxies: scaling relations
• Multiwavelength Constraints on Pulsar Populations in the Galactic Center
• Long-term evolution of massive black hole binaries. IV. Mergers of galaxies with collisionally relaxed nuclei
• Environmental Effects for Gravitational-wave Astrophysics
• Dynamical evolution of the young stars in the Galactic center: N-body simulations of the S-stars
• Proper motions of the Arches cluster with Keck-LGS Adaptive Optics: the first kinematic mass measurement of the Arches
• The nuclear cluster of the Milky Way: Our primary testbed for the interaction of a dense star cluster with a massive black hole
• The distribution of old stars around the Milky Way's central black hole I: Star counts
• Perturbations of Intermediate-mass Black Holes on Stellar Orbits in the Galactic Center
• The Nuclear Cluster of the Milky Way: Total Mass and Luminosity (long version)
• Near-infrared proper motions and spectroscopy of infrared excess sources at the Galactic Center
• Testing the No-Hair Theorem with Observations of Black Holes in the Electromagnetic Spectrum
• Detection of Supermassive Black Holes in Two Virgo Ultracompact Dwarf Galaxies
• KMOS view of the Galactic Centre - II. Metallicity distribution of late-type stars
• Discovery of low-metallicity stars in the central parsec of the Milky Way
• KMOS view of the Galactic Centre I. Young stars are centrally concentrated
• Improved Dynamical Constraints on the Mass of the central Black Hole in NGC 404
• On the distribution of stellar remnants around massive black holes: slow mass segregation, star cluster inspirals and correlated orbits
• Secular Evolution Of Binaries Near Massive Black Holes: Formation of compact binaries, merger/collision products and G2-like objects
• The impact of realistic models of mass segregation on the event rate of extreme-mass ratio inspirals and cusp re-growth
• Secular Stellar Dynamics near a Massive Black Hole
• Galaxy Rotation and Rapid Supermassive Black Hole Binary Coalescence
• The MEGaN project II. Gravitational waves from intermediate mass- and binary black holes around a supermassive black hole
• 3D stellar kinematics at the Galactic center: measuring the nuclear star cluster spatial density profile, black hole mass, and distance
• The mean infrared emission of SagittariusA*
• Gamma-ray emission from massive stars interacting with AGN jets
• What is limiting near-infrared astrometry in the Galactic Center?
• Traces of past activity in the Galactic Centre
• A 3.5-million Solar Masses Black Hole in the Centre of the Ultracompact Dwarf Galaxy Fornax UCD3
• A Cool Accretion Disk around the Galactic Centre Black Hole
• Interstellar gas within $\sim 10$ pc of Sgr A${}^{\ast }$
• Gas dynamics of the central few parsec region of NGC 1068 fuelled by the evolving nuclear star cluster
• On post-Newtonian orbits and the Galactic-center stars
• The Progenitors of Type Ia Supernovae: II. Are they Double-Degenerate Binaries? The Symbiotic Channel
• Pulsar-Black Hole Binaries in the Galactic Center
• Black Hole Binaries in Galactic Nuclei and Gravitational Wave Sources
• The distribution of stars around the Milky Way's central black hole II: Diffuse light from sub-giants and dwarfs
• Chemical Features in the Circumnuclear Disk of the Galactic Center
• CMZoom: Survey Overview and First Data Release
• WIMP searches with gamma rays in the Fermi era: challenges, methods and results
• AMUSE-Field I: Nuclear X-ray Properties of Local Field and Group Spheroids across the Stellar Mass Scale
• GC-IRS13E - A puzzling association of three early-type stars
• Holographic Imaging of Crowded Fields: High Angular Resolution Imaging with Excellent Quality at Very Low Cost
• Towards relativistic orbit fitting of Galactic center stars and pulsars
• Mass estimates from stellar proper motions: The mass of $\omega$ Centauri
• Kinematic Structure of the Galactic Center S-cluster
• Prospects for measuring supermassive black hole masses with future extremely large telescopes
• Test of Einstein equivalence principle near the Galactic center supermassive black hole
• Misaligned streamers around a galactic centre black hole from a single cloud's infall
• Testing the No-Hair Theorem with Observations of Black Holes in the Electromagnetic Spectrum
• Possible Origin of the G2 Cloud from the Tidal Disruption of a Known Giant Star by Sgr A*
• Constraining the initial mass function of stars in the Galactic Centre
• The extreme luminosity states of Sagittarius A*
• Observation of S4716 -- a Star with a 4 yr Orbit around Sgr A*
• Isolated massive stars in the Galactic center: The dynamic contribution from the Arches and Quintuplet star clusters
• Star Formation in the vicinity of Nuclear Black Holes: Young Stellar Objects close to Sgr A*
• Substellar Objects in Nearby Young Clusters (SONYC) VIII: Substellar population in Lupus 3
• Constraining nuclear star cluster formation using MUSE-AO observations of the early-type galaxy FCC47
• Gamma-ray and X-ray emission from the Galactic Centre: hints on the nuclear star cluster formation history
• Reconnection-driven flares in 3D black hole magnetospheres -- A scenario for hot spots around Sagittarius A*
• Young, Massive Star Candidates Detected throughout the Nuclear Star Cluster of the Milky Way
• ALMA View of the Circum-nuclear Disk of the Galactic Center; Tidally-disrupted Molecular Clouds falling to the Galactic Center
• Isotropic-Nematic Phase Transitions in Gravitational Systems
• The Second Galactic Center Black Hole?; A Possible Detection of Ionized Gas Orbiting around an IMBH embedded in the Galactic Center IRS13E complex
• On rapid migration and accretion within disks around supermassive black holes
• Revealing the Formation of the Milky Way Nuclear Star Cluster via Chemo-Dynamical Modeling
• On the origin of the B-stars in the Galactic center
• Near-Infrared Variability Study of the Central 2.3 arcmin x 2.3 arcmin of the Galactic Centre II. Identification of RR Lyrae Stars in the Milky Way Nuclear Star Cluster
• The habitability of the Milky Way during the active phase of its central supermassive black hole
• A cosmological view of extreme mass-ratio inspirals in nuclear star clusters
• Properties of the Compact HII Region Complex G-0.02-0.07
• The Galactic Center as a laboratory for theories of gravity and dark matter
• Coronal radiation of a cusp of spun-up stars and the X-ray luminosity of Sgr A*
• On the relation between the mass of Compact Massive Objects and their host galaxies
• Galactic-center S-Stars as a prospective test of the Einstein Equivalence Principle
• The inner cavity of the circumnuclear disc
• HST Observations of the Stellar Distribution Near Sgr A*
• Can Star-Disk Collisions Explain the Missing Red Giants Problem in the Galactic Center?
• Gravitational Encounters and the Evolution of Galactic Nuclei. I. Method
• On the Newtonian and Spin-induced Perturbations felt by the Stars Orbiting around the Massive Black Hole in the Galactic Center
• A minor merger scenario for the ultraluminous X-ray source ESO 243-49 HLX-1
• Dark matter concentrations in galactic nuclei according to polytropic models
• Star Formation and Dynamics in the Galactic Centre
• The MBHBM${}^{\star }$ Project -- II. Molecular Gas Kinematics in the Lenticular Galaxy NGC 3593 Reveal a Supermassive Black Hole
• Properties of bow-shock sources at the Galactic center
• Gravitational Encounters and the Evolution of Galactic Nuclei. IV. Captures Mediated by Gravitational-Wave Energy Loss
• Colliding Winds in and around the Stellar Group IRS 13E at the Galactic Center
• Near-infrared polarimetry as a tool for testing properties of accreting super-massive black holes
• The influence of the secular perturbation of an intermediate-mass companion: I. Eccentricity excitation of disk stars at the Galactic center
• Milky Way White Dwarfs as Sub-GeV to Multi-TeV Dark Matter Detectors
• Dust within the old nuclear star cluster in the Milky Way
• Spin Evolution of Supermassive Black Holes and Galactic Nuclei
• Stellar Populations in the Central 0.5 pc of Our Galaxy III: The Dynamical Sub-structures
• A proper motion catalogue for the Milky Way's nuclear stellar disc
• Gravitational Encounters and the Evolution of Galactic Nuclei. II. Classical and Resonant Relaxation
• Secular Dynamical Anti-Friction in Galactic Nuclei
• A binary system in the S cluster close to the supermassive black hole Sagittarius A*
• A new bow-shock source with bipolar morphology in the vicinity of Sgr A*
• Forming circumnuclear disks and rings in galactic nuclei: a competition between supermassive black hole and nuclear star cluster
• ALMA and VLA observations of emission from the environment of Sgr A*
• First results from a large-scale proper motion study of the Galactic Centre
• Rotating Ionized Gas Ring around the Galactic Center IRS13E3
• AGN Activity in Nucleated Galaxies as Measured by Chandra
• ALMA backed NIR high resolution integral field spectroscopy of the NUGA galaxy NGC 1433
• Constraints on the Galactic Centre environment from \textit{Gaia} hypervelocity stars III: Insights on a possible companion to Sgr A*
• Kinematic data rebuild the Nuclear star cluster as the most metal rich region of the Galaxy
• Sgr A* and its Environment: Low Mass Star Formation, the Origin of X-ray Gas and Collimated Outflow
• Near-Infrared Variability Study of the Central 2.3 arcmin x 2.3 arcmin of the Galactic Centre I. Catalog of Variable Sources
• Addendum to "Absorption of a massive scalar field by a charged black hole"
• Comparative analysis of the influence of Sgr A* and nearby active galactic nuclei on the mass loss of known exoplanets
• Evolution of supermassive black hole binaries and tidal disruption rates in nonspherical galactic nuclei
• Effects of turbulence in the Circumnuclear Disk
• Orbit-superposition models of discrete, incomplete stellar kinematics: application to the Galactic centre
• A Clustering Analysis of the Morphology of the 130 GeV Gamma-Ray Feature
• Simulating the tidal disruption of stars by stellar-mass black holes using moving-mesh hydrodynamics
• Dark-matter-like solutions to Einstein's unified field equations
• Adaptive optics assisted near-infrared polarization measurements of sources in the Galactic Center
• Neutron Star Structure in Hořava-Lifshitz Gravity
• Hanging on the cliff: Extreme mass ratio inspiral formation with local two-body relaxation and post-Newtonian dynamics
• Order-disorder phase transition in black-hole star clusters -- III. A mono-energetic cluster
• Smooth kinematic and metallicity gradients reveal that the Milky Way's nuclear star cluster and disc might be part of the same structure
• 2D kinematic study of the central region of NGC 4501
• Transient Events in Archival Very Large Array Observations of the Galactic Center
• Revisiting Primordial Black Hole Capture by Neutron Stars
• Modified evolution of stellar binaries from supermassive black hole binaries
• Mid-Infrared studies of dusty sources in the Galactic Center
• How far actually is the Galactic Center IRS 13E3 from Sagittarius A${}^{\ast }$?
• Can a Satellite Galaxy Merger Explain the Active Past of the Galactic Center?
• On the possibility of a warped disc origin of the inclined stellar discs at the Galactic Centre
• The impact of gravitational lensing in the reconstruction of stellar orbits around Sgr A*
• Detecting Stars at the Galactic Centre via Synchrotron Emission
• Tidal Distortion of the Envelope of an AGB Star IRS 3 near Sgr A*
• A common origin for the circumnuclear disc and the nearby molecular clouds in the Galactic Centre
• Eccentricity distribution of extreme mass ratio inspirals
• Millisecond Pulsar Kicks Cause Difficulties in Explaining the Galactic Center Gamma-Ray Excess
• Sub-millimeter Detection of a Galactic Center Cool Star IRS 7 by ALMA
• Constraining a disformal Schwarzschild black hole in DHOST theories with the orbit of the S2 star
• Growing a nuclear star cluster from star formation and cluster mergers: The JWST NIRSpec view of NGC 4654
• Dynamical mass distribution and velocity structure of the Galactic centre
• Probing the formation of planetesimals in the Galactic Centre using Sgr A* flares
• ALMA Astrometry of the Objects within 0.5 pc of Sagittarius A${}^{\ast }$
• Candidate Young Stellar Objects in the S-cluster: The Kinematic Analysis of a Sub-population of the Low-mass G-objects close to Sgr A*
• Double progenitor origin of the S-star cluster
• Quadrupole stellar oscillations: The impact of gravitational waves from the Galactic Center
• A stellar fly-by close to the Galactic centre: Can we detect stars on highly-relativistic orbits?
• Selected Chapters on Active Galactic Nuclei as Relativistic Systems
• Profiling stellar environments of gravitational wave sources
• Can Massive Gravity Explain the Mass Discrepancy - Acceleration Relation of Disk Galaxies?
• Growth of A Massive Black Hole Via Tidal Disruption Accretion
• Self-consistent Solutions of Evolving Nuclear Star Clusters with Two-Dimensional Monte-Carlo Dynamical Simulations
• Observations of the 86 GHz SiO maser sources in the Central Parsec of the Galactic Centre
• On the Missing Red Giants near the Galactic Center
• Discovery of a Dense Association of Stars in the Vicinity of the Supermassive Black Hole Sgr A*
• Co-evolution of Nuclear Star Clusters and Massive Black Holes: Extreme Mass-Ratio Inspirals
• The Steady State of Intermediate-Mass Black Holes Near a Supermassive Black Hole
• Missing bright red giants in the Galactic center: A fingerprint of its once active state?
• Constraining Axion Dark Matter with Galactic-Centre Resonant Dynamics
• The Milky Way's nuclear star cluster and massive black hole
• The interaction between supermassive black holes and globular clusters
• Vanishing Compactness Gap and Fermionic Compact Dark Matter in Hořava-Lifshitz Gravity
• Massive black hole formation in dense stellar environments: Enhanced X-ray detection rates in high velocity dispersion nuclear star clusters
• Self-consistent modelling of the Milky Way's Nuclear Stellar Disc