The formation history of our Galaxy's nuclear stellar disc constrained from HST observations of the Quintuplet field

Abstract

Until recently it was thought that the nuclear stellar disc at the centre of our Galaxy was formed via quasi-continuous star formation over billions of years. However, an analysis of GALACTICNUCLEUS survey data indicates that >80% of the mass of the stellar disc formed at least 8 Gyr ago and about 5% roughly 1 Gyr ago. Our aim is to derive new constraints on the formation history of the nuclear stellar disc. We analysed a catalogue of HST/WFC3-IR observations of the Quintuplet cluster field. From this catalogue, we selected about 24000 field stars that probably belong to the nuclear stellar disc. We used red clump giants to deredden the sample and fit the resulting F153M luminosity function with a linear combination of theoretical luminosity functions created from different stellar evolutionary models. We find that >70% of the stellar population in the nuclear disc probably formed more than 10 Gyr ago, while ~15% formed in an event (or series of events) ~1Gyr ago. Up to 10% of the stars appear to have formed in the past tens to hundreds of Myr. These results do not change significantly for reasonable variations in the assumed mean metallicity, sample selection, reddening correction, or stellar evolutionary models. We confirm previous work that changed the formation paradigm for stars in the Galactic Centre. The nuclear stellar disc is indeed a very old structure. There seems to have been little star formation activity between its formation and about 1 Gyr ago.

Accepted for publication in A&A

References in corpus (22)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Improving PARSEC models for very low mass stars
• New PARSEC evolutionary tracks of massive stars at low metallicity: testing canonical stellar evolution in nearby star forming dwarf galaxies
• Kraken reveals itself -- the merger history of the Milky Way reconstructed with the E-MOSAICS simulations
• The updated BaSTI stellar evolution models and isochrones: II. alpha-enhanced calculations
• The Initial Mass Function of the Massive Star-forming Region NGC 3603 from Near-Infrared Adaptive Optics observations
• Constraining the thermally pulsing asymptotic giant branch phase with resolved stellar populations in the Large Magellanic Cloud
• 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
• The nuclear cluster of the Milky Way: Our primary testbed for the interaction of a dense star cluster with a massive black hole
• The inside-out formation of nuclear discs and the absence of old central spheroids in barred galaxies of the TIMER survey
• The Milky Way's nuclear stellar disc: A dynamically cool and metal-rich component formed from the Central Molecular Zone?
• SPISEA: A Python-Based Simple Stellar Population Synthesis Code for Star Clusters
• Dynamically Driven Inflow onto the Galactic Center and its Effect upon Molecular Clouds
• The Star Formation History of the Milky Way's Nuclear Star Cluster
• GALACTICNUCLEUS: A high-angular-resolution $JH{K}_s$ imaging survey of the Galactic centre. IV. Extinction maps and de-reddened photometry
• Mira variables in the Milky Way's nuclear stellar disc: discovery and classification
• The Quintuplet Cluster: Extended Structure and Tidal Radius
• 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
• Measuring the Orbits of the Arches and Quintuplet Clusters using HST and Gaia: Exploring Scenarios for Star Formation Near the Galactic Center

Cited by in corpus (7)

• The S stars' zone of avoidance in the Galactic center
• A Wide Metallicity Range for Gyr-old Stars in the Nuclear Star Cluster
• Double progenitor origin of the S-star cluster
• Metallicity-dependent kinematics and orbits in the Milky Way's nuclear stellar disc
• The Galactic Center with Roman
• Age and metallicity of the Milky Way's nuclear star cluster studied at 3 pc from Sagittarius A*
• Infrared photometry and CaT spectroscopy of the most metal-poor in-situ globular cluster VVV-CL001