The globular cluster systems of the milky way and the Sagittarius dwarf galaxy
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Fecha
2023
Autores
Facultad/escuela
Idioma
es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
The VISTA Variables in the Via Lactea Survey (VVV) and its Extension (VVVX) allow us to probe ´
previously 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
investigate them to reveal their true nature. In particular, I am looking for new candidate globular
clusters (GCs) located in the Galactic bulge and disk, with the aim of completing the census of
the MW GC system. I searched and characterized new star clusters, using a combination of the
near-infrared (IR) VVV-VVVX survey and Two Micron All Sky survey (2MASS) datasets, and
the optical Gaia Data Releases (DR2, EDR3 and DR3) photometry and its precise astrometry and
proper motions (PMs). Performing a PM-decontamination procedure, I built final catalogues with
high-likely cluster members, on which I carried out a detailed photometric analysis. I estimated
the main physical parameters, such as reddenings and extinction, heliocentric and Galactocentric
distances, mean cluster PMs, metallicities, ages, integrated luminosities, and structural parameters
(core and tidal radii). 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, and 4 are old open clusters in
the MW bulge and disk, whereas other 17 GCs belonging to the Sagittarius dwarf galaxy. Finally,
for 11 bound systems, I collected radial velocity informations (from H-/K-band spectra and/or Gaia
DR3 datasets) in order to reconstruct their orbital history for the first time, thus associating these
clusters to the relative Galactic components and understand their (in-situ or ex-situ) origin.
Notas
Tesis (Doctora en Astrofísica)
Palabras clave
Galaxias Cúmulos, Estrellas, Cúmulos Globulares, Galaxias, Formación