Searching for new GC candidates in the Galactic plane with the VVV, Gaia and 2MASS surveys
Elisa Garro (ESO - Chile)
Tuesday 10/12/2024 @ 14:30, Sala Antonio Sollima (IV piano Battiferro)
The VISTA Variables in the Via Láctea Survey and its Extension (VVV/VVVX) allow probing unexplored regions of the inner Milky Way (MW), especially those that are affected by stellar crowding and strong extinction. My long-term goal is to identify new star clusters and reveal their true nature. I looked for new candidate globular clusters (GCs) in the Galactic bulge/disk, with the aim of completing the census of the MWGC system. I used a combination of near-IR VVV-VVVX and 2MASS datasets, and optical Gaia DR2/EDR3/DR3 photometry, its precise astrometry and proper motions (PMs). Performing a PM-decontamination procedure, I built catalogues with high-likely cluster members, on which I performed a photometric analysis. I estimated main physical parameters: reddening, extinction, heliocentric and Galactocentric distances, mean cluster PMs, metallicities, ages, luminosities, structural parameters. I analysed 34 new GC candidates in the MW and 21 in the Sagittarius dwarf galaxies, confirming (photometrically) the GC nature for 17 of them, 4 are old open clusters in the MW, whereas 17 GCs belonging to the Sagittarius galaxy. For 11 bound systems, I collected RVs in order to reconstruct their orbital history for the first time, associating these clusters to the relative Galactic components and understand their origin.