Journey into the Galactic Heart: Illuminating the Enigma of the Nuclear Star Cluster and the Nuclear Stellar Disc.

The innermost regions of most galaxies are characterised by the presence of extremely dense nuclear star clusters, which sometimes appear together with larger stellar structures known as nuclear stellar discs. 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. In this context, the Milky Way’s centre, which hosts both structures, appears as a unique template to understand their relation and formation scenario. Using photometric, metallicity and kinematic catalogues, we analysed the relation between these two Galactic centre components and study their stellar populations. We detect kinematic and metallicity gradients along the line of sight, suggesting a smooth transition between 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.