Vorschau

PDF, Englisch - Hauptdokument Download (42MB) | Lizenz: Dynamics of the Milky Way Disk and Spectroscopic Analysis of ω Centauri von Nitschai, Maria Selina steht unter einer Creative Commons Namensnennung 4.0

Abstract

The Milky Way is the perfect laboratory to study galaxy evolution and formation due to our unique position inside its disk. Recent surveys and instruments can provide an extensive amount of data for our Galaxy that are the key to revealing its assembly history. In this thesis, I first combine Gaia EDR3 and APOGEE data throughout Galactocentric radii between 5.0 ≤ R ≤ 19.5 kpc and construct a dynamical model. Using the spherically-aligned Jeans Anisotropic Method I model the stellar velocities and the velocity dispersions of the Galactic disk. This model can capture the main kinematic features and give an accurate mass density of the Galaxy, making it a fundamental test for both galaxy dynamics in general and the mass distribution of the Milky Way. Further, I focus on Omega Centauri (ω Cen), the most massive globular cluster in the Milky Way, which has long been suspected to be the stripped nucleus of a dwarf galaxy that fell into the Galaxy a long time ago. This merger event was the last significant merger the Galaxy has experienced and is therefore an important event in its evolution. Firstly, I present a MUSE spectroscopic dataset with more than 300,000 extracted stellar spectra, reaching more than two magnitudes below the main sequence turn-off. This massive spectroscopic dataset will enable future studies that will transform our understanding of ω Cen. Secondly, I investigate the underlying metallicity distributions as well as the spatial variations of the populations within the cluster for the red giant branch stars. For that, I combine the new MUSE spectroscopy with new HST photometry and show that there appears to be no gradient in metallicity, indicating that the cluster is well mixed and any merge happened many years ago. Finally, I conclude with future studies that will investigate the stellar populations, ages, abundances, kinematics, and dynamics of ω Cen in great detail.