Smooth kinematic and metallicity gradients reveal that the Milky Way's nuclear star cluster and disc might be part of the same structure
arXiv:2309.07219 · doi:10.1051/0004-6361/202347421
Abstract
The innermost regions of most galaxies are characterised by the presence of extremely dense nuclear star clusters. Nevertheless, these clusters are not the only stellar component present in galactic nuclei, where larger stellar structures known as nuclear stellar discs, have also been found. Understanding the relation between nuclear star clusters and nuclear stellar discs is challenging due to the large distance towards other galaxies which limits their analysis to integrated light. The Milky Way's centre, at only 8 kpc, hosts a nuclear star cluster and a nuclear stellar disc, constituting a unique template to understand their relation and formation scenario. We aim to study the kinematics and stellar metallicity of stars from the Milky Way's nuclear star cluster and disc to shed light on the relation between these two Galactic centre components. We used publicly available photometric, proper motions, and spectroscopic catalogues to analyse a region of centred on the Milky Way's nuclear star cluster. We built colour magnitude diagrams, and applied colour cuts to analyse the kinematic and metallicity distributions of Milky Way's nuclear star cluster and disc stars with different extinction along the line of sight. We detect kinematics and metallicity gradients for the analysed stars along the line of sight towards the Milky Way's nuclear star cluster, suggesting a smooth transition between the nuclear stellar disc and cluster. We also find a bi-modal metallicity distribution for all the analysed colour bins, which is compatible with previous work on the bulk population of the nuclear stellar disc and cluster. Our results suggest that these two Galactic centre components might be part of the same structure with the Milky Way's nuclear stellar disc being the grown edge of the nuclear star cluster.
arXiv commentAccepted for publication in A&A. 13 pages, 9 figures
References in corpus (70)
- A new extensive library of PHOENIX stellar atmospheres and synthetic spectra
- Detection of the gravitational redshift in the orbit of the star S2 near the Galactic centre massive black hole
- Relativistic redshift of the star S0-2 orbiting the Galactic center supermassive black hole
- The Nuclear Bulge of the Galaxy. III. Large-Scale Physical Characteristics of Stars and Interstellar Matter
- Nuclear Star Clusters
- The nuclear star cluster of the Milky Way: proper motions and mass
- Line derived infrared extinction towards the Galactic Center
- Interstellar Extinction Law in the J, H, and Ks Bands toward the Galactic Center
- The ACS Survey of Galactic Globular Clusters: M54 and Young Populations in the Sagittarius Dwarf Spheroidal Galaxy
- 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
- HST Proper Motions and Stellar Dynamics in the Core of the Globular Cluster 47 Tucanae
- Interstellar Extinction Law toward the Galactic Center II: V, J, H, and Ks Bands
- The star formation history of the Milky Way's Nuclear Star Cluster
- Origin and growth of nuclear star clusters around massive black holes
- The Evolution of the Globular Cluster System in a Triaxial Galaxy: Can a Galactic Nucleus Form by Globular Cluster Capture?
- Large scale kinematics and dynamical modelling of the Milky Way nuclear star cluster
- Kinematics of the old stellar population at the Galactic Center
- HST Paschen alpha and 1.9 micron imaging of Sgr A West
- Gas flow in barred potentials
- Early formation and recent starburst activity in the nuclear disc of the Milky Way
- Kinematic signatures of nuclear discs and bar-driven secular evolution in nearby galaxies of the MUSE TIMER project
- The Milky Way's nuclear star cluster: Old, metal-rich, and cuspy
- HST Paschen-alpha Survey of the Galactic Center: Data Reduction and Products
- The nuclear cluster of the Milky Way: Our primary testbed for the interaction of a dense star cluster with a massive black hole
- The Nuclear Cluster of the Milky Way: Total Mass and Luminosity (long version)
- KMOS view of the Galactic Centre - II. Metallicity distribution of late-type stars
- The Link between Warm Molecular Disks in Maser Nuclei and Star Formation near the Black Hole at the Galactic Center
- GALACTICNUCLEUS: A high angular resolution imaging survey of the Galactic Centre. I. Methodology, performance, and near-infrared extinction towards the Galactic Centre
- HST/NICMOS Paschen-alpha Survey of the Galactic Center: Overview
- The inside-out formation of nuclear discs and the absence of old central spheroids in barred galaxies of the TIMER survey
- Effects of Gas on Formation and Evolution of Stellar Bars and Nuclear Rings in Disk Galaxies
- New insights on the formation of nuclear star clusters
- Henize 2-10: the ongoing formation of a nuclear star cluster around a massive black hole
- 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
- On the rotation of nuclear star clusters formed by cluster-inspirals
- New constraints on the structure of the nuclear stellar cluster of the Milky Way from star counts and MIR imaging
- Nuclear Stellar Disks in Spiral Galaxies
- Age and mass segregation of multiple stellar populations in galactic nuclei and their observational signatures
- The Milky Way's nuclear stellar disc: A dynamically cool and metal-rich component formed from the Central Molecular Zone?
- Formation and evolution of nuclear star clusters with in-situ star-formation: Nuclear cores and age segregation
- Holographic Imaging of Crowded Fields: High Angular Resolution Imaging with Excellent Quality at Very Low Cost
- Mapping the stellar age of the Milky Way bulge with the VVV. III. High resolution reddening map
- Jeans modelling of the Milky Way's nuclear stellar disc
- The complex nature of the nuclear star cluster in FCC 277
- Star formation history and metallicity in the Galactic inner bulge revealed by the red giant branch bump
- The Star Formation History of the Milky Way's Nuclear Star Cluster
- Asymmetric spatial distribution of sub-solar metallicity stars in the Milky Way nuclear star cluster
- Constraining nuclear star cluster formation using MUSE-AO observations of the early-type galaxy FCC47
- Clocking the assembly of double-barred galaxies with the MUSE TIMER project
- On the origin of a rotating metal-poor stellar population in the Milky Way Nuclear Cluster
- GALACTICNUCLEUS: A high-angular-resolution JHKs imaging survey of the Galactic centre III. Evidence for wavelength dependence of the extinction curve in the near-infrared
- GALACTICNUCLEUS: A high-angular-resolution imaging survey of the Galactic centre. IV. Extinction maps and de-reddened photometry
- Revealing the Formation of the Milky Way Nuclear Star Cluster via Chemo-Dynamical Modeling
- A new method for age-dating the formation of bars in disc galaxies: The TIMER view on NGC1433's old bar and the inside-out growth of its nuclear disc
- The nuclear star cluster and nuclear stellar disc of the Milky Way: Different stellar population and star formation history
- A KMOS survey of the nuclear disk of the Milky Way I: Survey design and metallicities
- Star formation at the Galactic Centre: coevolution of multiple young stellar discs
- Dust within the old nuclear star cluster in the Milky Way
- A proper motion catalogue for the Milky Way's nuclear stellar disc
- Evidence of an age gradient along the line of sight in the nuclear stellar disc of the Milky Way
- Kinematic data rebuild the Nuclear star cluster as the most metal rich region of the Galaxy
- Stellar cluster formation in a Milky Way-sized galaxy at z>4 -- I. The proto-globular cluster population and the imposter amongst us
- A first glimpse at the line-of-sight structure of the Milky Way's nuclear stellar disc
- Spectroscopically Identified Intermediate Age Stars at 0.5 - 3 pc Distance from Sgr A*
- Distance to the Brick cloud using stellar kinematics
- Spatially Resolving the Star Formation Histories of Three Nearby Nuclear Star Clusters
- Searching for clues of past binary supermassive black hole mergers in nuclear star clusters
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- A spectroscopic map of the Galactic centre -- Observations and resolved stars
- Metallicity-dependent kinematics and orbits in the Milky Way's nuclear stellar disc
- Chemical Evolution in Nuclear Stellar Discs
- Chemical analysis of the Milky Way's Nuclear Star Cluster: Evidence for a metallicity gradient
- Supergiant GCIRS 22 in the Milky Way Nuclear Star Cluster: Revised alpha abundances