The structure of the nuclear stellar cluster of the Milky Way

Abstract

We present high-resolution seeing limited and AO NIR imaging observations of the stellar cluster within about one parsec of Sgr A*, the massive black hole at the centre of the Milky Way. Stellar number counts and the diffuse background light density were extracted from these observations in order to examine the structure of the nuclear stellar cluster.Our findings are as follows: (a) A broken-power law provides an excellent fit to the overall structure of the GC nuclear cluster. The power-law slope of the cusp is $\Gamma =0.19\pm 0.05$, the break radius is $R_{\mathrm{break}}=6.0^{\prime \prime }\pm 1.0^{\prime \prime }$ or $0.22\pm 0.04$ pc, and the cluster density decreases with a power-law index of $\Gamma =0.75\pm 0.1$ outside of $R_{\mathrm{break}}$. (b) Using the best velocity dispersion measurements from the literature, we derive higher mass estimates for the central parsec than assumed until now. The inferred density of the cluster at the break radius is $2.8\pm 1.3\times 10^6{\mathrm{M}}_{\odot }\mathrm{p}{\mathrm{c}}^{-3}$. This high density agrees well with the small extent and flat slope of the cusp. Possibly, the mass of the stars makes up only about 50% of the total cluster mass. (c) Possible indications of mass segregation in the cusp are found (d) The cluster appears not entirely homogeneous. Several density clumps are detected that are concentrated at projected distances of $R=3^{\prime \prime }$ and $R=7^{\prime \prime }$ from Sgr A*.(e) There appears to exist an under-density of horizontal branch/red clump stars near $R=5^{\prime \prime }$, or an over-density of stars of similar brightness at $R=3^{\prime \prime }$ and $R=7^{\prime \prime }$. (f) The extinction map in combination with cometary-like features in an L'-band image may provide support for the assumption of an outflow from Sgr A*.

arXiv commentaccepted for publication by A&A; please contact first author for higher quality figures

References in corpus (56)

• The Structure of Cold Dark Matter Halos
• Evolutionary tracks and isochrones for low- and intermediate-mass stars: from 0.15 to 7 M_sun, and from Z=0.0004 to 0.03
• On the Fate of Gas Accreting at a Low Rate onto a Black Hole
• Closest Star Seen Orbiting the Supermassive Black Hole at the Centre of the Milky Way
• The First Measurement of Spectral Lines in a Short-Period Star Bound to the Galaxy's Central Black Hole: A Paradox of Youth
• The Two Young Star Disks in the Central Parsec of the Galaxy: Properties, Dynamics and Formation
• Near-infrared flares from accreting gas around the supermassive black hole at the Galactic Centre
• The Stellar Cusp Around the Supermassive Black Hole in the Galactic Center
• A jet model for the broadband spectrum of XTE J1118+480: Synchrotron emission from radio to X-rays in the Low/Hard spectral state
• The Supermassive Black Hole at the Galactic Center
• The Nuclear Bulge of the Galaxy. III. Large-Scale Physical Characteristics of Stars and Interstellar Matter
• The Accelerations of Stars Orbiting the Milky Way's Central Black Hole
• Stellar disk in the galactic center -- a remnant of a dense accretion disk?
• Analysis of isoplanatic high resolution stellar fields by Starfinder code
• Stellar Dynamics in the Galactic centre: Proper Motions and Anisotropy
• Stellar dynamics in the central arcsecond of our galaxy
• A Geometric Determination of the Distance to the Galactic Center
• Stellar Processes Near the Massive Black Hole in the Galactic Center
• Variable Infrared Emission from the Supermassive Black Hole at the Center of the Milky Way
• A Jet-ADAF model for Sgr A*
• The effect of mass-segregation on gravitational wave sources near massive black holes
• Stellar remnants in galactic nuclei: mass segregation
• HCN and HCO+ Observations of the Galactic Circumnuclear Disk
• A Cluster of Black Holes at the Galactic Center
• Detection of the Intrinsic Size of Sagittarius A* through Closure Amplitude Imaging (includes Online Supporting Material)
• Polarimetry of near-infrared flares from Sagittarius A*
• An Extended Star Formation History for the Galactic Center from Hubble Space Telescope/NICMOS Observations
• An Overabundance of Transient X-ray Binaries within 1 pc of the Galactic Center
• The "missing" YSOs in the central parsec of the Galaxy: evidence for star formation in a massive accretion disk and a top-heavy IMF
• Models of Galaxies with Central Black Holes: Adiabatic Growth in Spherical Galaxies
• JHKL Photometry and the K-band Luminosity Function at the Galactic Center
• The nature of the Galactic Center source IRS 13 revealed by high spatial resolution in the infrared
• HST Paschen alpha and 1.9 micron imaging of Sgr A West
• The Flare Activity of SgrA*; New Coordinated mm to X-Ray Observations
• The distribution of stars near the super-massive black hole in the Galactic Center
• Near-infrared polarimetry setting constraints on the orbiting spot model for Sgr A* flares
• Dynamics of galaxy cores and supermassive black holes
• A Chandra Catalog of X-ray Sources in the Central 150 pc of the Galaxy
• Radiatively Inefficient Accretion Flow Models of Sgr A*
• N-Body Growth of a Bahcall-Wolf Cusp Around a Black Hole
• II. Accurate Positions and Proper Motions of Stellar SiO Masers near the Galactic Center
• K-band polarimetry of an Sgr A* flare with a clear sub-flare structure
• Dynamical Cusp Regeneration
• Massive stars in sub-parsec rings around galactic centers
• A Black Hole in the Galactic Center Complex IRS 13E?
• Orbital capture of stars by a massive black hole via exchanges with compact remnants
• Weighing the young stellar discs around Sgr A*
• Accretion of stars on to a massive black hole: A realistic diffusion model and numerical studies
• Near-Infrared Microlensing of Stars by the Super-Massive Black Hole in the Galactic Center
• High Precision Stellar Radial Velocities in the Galactic Center
• Weighing the cusp at the Galactic Centre
• Proper Motions of Ionized Gas at the Galactic Center: Evidence for Unbound Orbiting Gas
• VLT L-band mapping of the Galactic Center IRS 3-IRS 13 region Evidence for new Wolf-Rayet type stars
• X-ray Radiation from the Annihilation of Dark Matter at the Galactic Center
• Detection of the Sgr A* activity at 3.8 and 4.8 microns with NACO
• Pinpointing the massive black hole in the Galactic Center with gravitationally lensed stars

Cited by in corpus (176)

• 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 Galactic Center Massive Black Hole and Nuclear Star Cluster
• First Sagittarius A* Event Horizon Telescope Results. VI: Testing the Black Hole Metric
• What Drives the Growth of Black Holes?
• Gravitational waves from scattering of stellar-mass black holes in galactic nuclei
• Detection of a Gamma-Ray Source in the Galactic Center Consistent with Extended Emission from Dark Matter Annihilation and Concentrated Astrophysical Emission
• 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
• The nuclear star cluster of the Milky Way: proper motions and mass
• Galactic Searches for Dark Matter
• Quantifying the Coexistence of Massive Black Holes and Dense Nuclear Star Clusters
• Strong mass segregation around a massive black hole
• The Coincidence of Nuclear Star Clusters and Active Galactic Nuclei
• 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
• Co-Evolution of Galactic Nuclei and Globular Cluster Systems
• Masses and Scaling Relations for Nuclear Star Clusters, and their Coexistence with Central Black Holes
• High angular resolution integral-field spectroscopy of the Galaxy's nuclear cluster: a missing stellar cusp?
• The NGC 404 Nucleus: Star Cluster and Possible Intermediate Mass Black Hole
• Stellar Dynamics and Stellar Phenomena Near A Massive Black Hole
• 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
• The Tidal Disruption of Giant Stars and Their Contribution to the Flaring Supermassive Black Hole Population
• Resonant relaxation and the warp of the stellar disc in the Galactic centre
• Enhanced tidal disruption rates from massive black hole binaries
• Kinematics of the old stellar population at the Galactic Center
• The Milky Way's Supermassive Black Hole: How good a case is it? A Challenge for Astrophysics & Philosophy of Science
• Evidence for a Long-Standing Top-Heavy IMF in the Central Parsec of the Galaxy
• The HST/ACS Coma Cluster Survey. X. Nuclear star clusters in low-mass early-type galaxies: scaling relations
• Simulations of the formation of stellar discs in the Galactic centre via cloud-cloud collisions
• Stellar Populations in the Central 0.5 pc of the Galaxy I: A New Method for Constructing Luminosity Functions and Surface-Density Profiles
• Gravitational wave sources from inspiralling globular clusters in the Galactic Centre and similar environments
• A near-infrared survey of Miras and the distance to the Galactic Centre
• The Milky Way's nuclear star cluster: Old, metal-rich, and cuspy
• Dynamical evolution of the young stars in the Galactic center: N-body simulations of the S-stars
• The proper motion of the Arches cluster with Keck Laser-Guide Star Adaptive Optics
• The nuclear cluster of the Milky Way: Our primary testbed for the interaction of a dense star cluster with a massive black hole
• Radiation pressure and absorption in AGN: results from a complete unbiased sample from Swift
• The distribution of old stars around the Milky Way's central black hole I: Star counts
• On the nature of the fast moving star S2 in the Galactic Center
• The Nuclear Cluster of the Milky Way: Total Mass and Luminosity (long version)
• A New Secular Instability of Eccentric Stellar Disks Around Supermassive Black Holes, with Application to the Galactic Center
• Absorption Line Survey of H3+ toward the Galactic Center Sources II. Eight Infrared Sources within 30 pc of the Galactic Center
• KMOS view of the Galactic Centre I. Young stars are centrally concentrated
• Interaction of massive black hole binaries with their stellar environment: III. Scattering of bound stars
• The distribution of stars around the Milky Way's black hole III: Comparison with simulations
• Red giant stellar collisions in the Galactic Centre
• Secular Stellar Dynamics near a Massive Black Hole
• A numerical study of vector resonant relaxation
• Spoon-Feeding Giant Stars to Supermassive Black Holes: Episodic Mass Transfer from Evolving Stars and Their Contribution to the Quiescent Activity of Galactic Nuclei
• Are nuclear star clusters the precursors of massive black holes?
• 3D stellar kinematics at the Galactic center: measuring the nuclear star cluster spatial density profile, black hole mass, and distance
• Stellar Tidal Disruption Events with Abundances and Realistic Structures (STARS): Library of Fallback Rates
• An upper limit on the spin of SgrA${}^{\ast }$ based on stellar orbits in its vicinity
• Traces of past activity in the Galactic Centre
• Binary dynamics near a massive black hole
• High Eccentricities and High Masses Characterize Gravitational-wave Captures in Galactic Nuclei as Seen by Earth-based Detectors
• GALACTICNUCLEUS: A high-angular-resolution JHKs imaging survey of the Galactic centre II. First data release of the catalogue and the most detailed CMDs of the GC
• First proper motions of thin dust filaments at the Galactic Center
• Production of Hypervelocity Stars through Encounters with Stellar-Mass Black Holes in the Galactic Centre
• Is there a Supermassive Black Hole at the Center of the Milky Way?
• Explaining the Orbits of the Galactic Center S-Stars
• Near infrared flares of Sagittarius A*: Importance of near infrared polarimetry
• Interstellar gas within $\sim 10$ pc of Sgr A${}^{\ast }$
• Tracing intermediate-mass black holes in the Galactic Centre
• On post-Newtonian orbits and the Galactic-center stars
• Cometary shaped sources at the Galactic Center - Evidence for a wind from the central 0.2 pc
• Analytic study of mass segregation around a massive black hole
• Origin of the S Stars in the Galactic Center
• Orbits Around Black Holes in Triaxial Nuclei
• The distribution of stars around the Milky Way's central black hole II: Diffuse light from sub-giants and dwarfs
• Virgo Redux: The Masses and Stellar Content of Nuclei in Early-Type Galaxies from Multi-Band Photometry and Spectroscopy
• An Ultra-deep Chandra Catalog of X-ray Point Sources in the Galactic Center Star Cluster
• The birth of a supermassive black hole binary
• Detecting pulsars in the Galactic centre
• On Detecting Millisecond Pulsars at the Galactic Center
• The S-Star Cluster at the Center of the Milky Way: On the nature of diffuse NIR emission in the inner tenth of a parsec
• Influence of a stellar cusp on the dynamics of young stellar discs and the origin of the S-stars in the Galactic Centre
• Quiescent and active galactic nuclei as factories of merging compact objects in the era of gravitational-wave astronomy
• Misaligned streamers around a galactic centre black hole from a single cloud's infall
• Radial Distribution of X-ray Point Sources near the Galactic Center
• Spectroscopic Detection of a Cusp of Late-type Stars around the Central Black Hole in the Milky Way
• Constraining the initial mass function of stars in the Galactic Centre
• Dark matter dynamics in Galactic center
• The extreme luminosity states of Sagittarius A*
• The Process of Stellar Tidal Disruption by Supermassive Black Holes. The first pericenter passage
• IRS 13N: a new comoving group of sources at the Galactic Center
• A Hybrid N-Body Code Incorporating Algorithmic Regularization and Post-Newtonian Forces
• Constraining the dark cusp in the Galactic Center by long-period binaries
• Localizing Sagittarius A* and M87 on Microarcsecond Scales with Millimeter VLBI
• Extreme mass ratio inspirals and tidal disruption events in nuclear clusters. I. Time dependent rates
• What stellar orbit is needed to measure the spin of the Galactic center black hole from astrometric data?
• Young, Massive Star Candidates Detected throughout the Nuclear Star Cluster of the Milky Way
• A Multiwavelength Study of Evolved Massive Stars in the Galactic Center
• The orbital motion of the Quintuplet cluster - a common origin for the Arches and Quintuplet clusters?
• On the number of young stellar discs in the Galactic Centre
• The fragmenting past of the disk at the Galactic Center : The culprit for the missing red giants
• 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
• Expectations for extreme-mass-ratio bursts from the Galactic Centre
• Accelerated orbital decay of supermassive black hole binaries in merging nuclear star clusters
• The Keplerian three-body encounter I. Insights on the origin of the S-stars and the G-objects in the Galactic center
• A cosmological view of extreme mass-ratio inspirals in nuclear star clusters
• Ejection of hypervelocity binary stars by a black hole of intermediate mass orbiting Sgr A*
• Coronal radiation of a cusp of spun-up stars and the X-ray luminosity of Sgr A*
• The Effectiveness of the Kozai Mechanism in the Galactic Centre
• Discovery of a Significant Magnetic CV Population in the Limiting Window
• Is there an intermediate massive black hole in the Galactic center: Imprints on the stellar tidal-disruption rate
• Ionized Gas in the Galactic Center: New Observations and Interpretation
• Angular Momentum and the Formation of Stars and Black Holes
• HST Observations of the Stellar Distribution Near Sgr A*
• The origin of S-stars and a young stellar disk: distribution of debris stars of a sinking star cluster
• M-Band Spectra of Dust Embedded Sources at the Galactic Center
• Modelling the formation of the circumnuclear ring in the Galactic centre
• Radial Velocities of Stars in the Galactic Center
• Secular theory of the orbital evolution of the young stellar disc in the Galactic Centre
• Star Formation and Dynamics in the Galactic Centre
• Dark matter concentrations in galactic nuclei according to polytropic models
• Mass Distribution in the Central Few Parsecs of Our Galaxy
• Eccentric disc instability in stellar discs formed from inspiraling gas clouds in the Galactic Centre
• Secular Dynamical Anti-Friction in Galactic Nuclei
• The enigma of GCIRS 3 - Constraining the properties of the mid-infrared reference star of the central parsec of the Milky Way with optical long baseline interferometry
• Spin Evolution of Supermassive Black Holes and Galactic Nuclei
• The coupling of a young stellar disc with the molecular torus in the Galactic centre
• Evolution of growing black holes in axisymmetric galaxy cores
• Perturbations induced by a molecular cloud on the young stellar disc in the Galactic Centre
• Circumnuclear Media of Quiescent Supermassive Black Holes
• On the dissolution of star clusters in the Galactic centre. I. Circular orbits
• ALMA and VLA observations of emission from the environment of Sgr A*
• Lecture notes on black hole binary astrophysics
• First results from a large-scale proper motion study of the Galactic Centre
• Forming circumnuclear disks and rings in galactic nuclei: a competition between supermassive black hole and nuclear star cluster
• A practical guide to the massive black hole cosmic history
• Constraints on the Galactic Centre environment from \textit{Gaia} hypervelocity stars III: Insights on a possible companion to Sgr A*
• High-speed molecular cloudlets around the Galactic Center supermassive black hole
• Near-Infrared Variability Study of the Central 2.3 arcmin x 2.3 arcmin of the Galactic Centre I. Catalog of Variable Sources
• Astrometric Detection of Intermediate-Mass Black Holes At the Galactic Centre
• The influence of dense gas rings on the dynamics of a stellar disk in the Galactic center
• Adaptive optics assisted near-infrared polarization measurements of sources in the Galactic Center
• Classification of Stellar Orbits in Axisymmetric Galaxies
• A Chandra Survey of Milky Way Globular Clusters II: Testing the Hills-Heggie Law
• Constraining the Stellar Mass Function in the Galactic Center via Mass Loss from Stellar Collisions
• Hanging on the cliff: Extreme mass ratio inspiral formation with local two-body relaxation and post-Newtonian dynamics
• The nuclear star cluster of the Milky Way
• First VLTI infrared spectro-interferometry on GCIRS 7 - Characterizing the prime reference source for Galactic center observations at highest angular resolution
• Mid-Infrared studies of dusty sources in the Galactic Center
• Evolution of eccentric stellar disks around supermassive black holes: the complex disk disruption dynamics and the milliparsec stars
• The Milky Way like galaxy NGC 6384 and its nuclear star cluster at high NIR spatial resolution using LBT/ARGOS commissioning data
• The formation and stability of a cold disc made out of stellar winds in the Galactic Centre
• Stellar transits in active galactic nuclei
• A common origin for the circumnuclear disc and the nearby molecular clouds in the Galactic Centre
• Flare emission from Sagittarius A*
• Stellar Relaxation Processes Near the Galactic Massive Black Hole
• Sculpting the Stellar Cusp in the Galactic Center
• Parameter Distributions of Binary Black Hole Mergers Near Supermassive Black Holes as Seen by Advanced Gravitational Wave Detectors
• $G$ Objects and primordial black holes
• Eccentricity distribution of extreme mass ratio inspirals
• Probing the formation of planetesimals in the Galactic Centre using Sgr A* flares
• Mapping the aliphatic hydrocarbon content of interstellar dust in the Galactic plane
• Dynamics around supermassive black holes
• Study of the Science Capabilities of PRIMA in the Galactic Center
• Dynamics of galactic nuclei: Mass segregation and collisions
• The Scientific Life Of John Bahcall
• High-spectral resolution M-band observations of CO Rot-Vib absorption lines towards the Galactic center
• On the Missing Red Giants near the Galactic Center
• Observational constraints on the formation and evolution of the Milky Way nuclear star cluster with Keck and Gemini
• Deformation of the Galactic Centre stellar cusp due to the gravity of a growing gas disc
• Gravitational waves from primordial black holes passing by neutron stars: observational prospects for the Galactic center
• NACO/SAM observations of sources at the Galactic Center
• The Milky Way's nuclear star cluster and massive black hole
• Composition of the galactic center star cluster: Population analysis from adaptive optics narrow band spectral energy distributions
• 4-8 GHz Fourier-domain Searches for Galactic Center Pulsars