A Study of Galactic and Extragalactic Evolution with the MUSE Integral-Field Spectrograph

Abstract

The Milky Way is by far the best-studied galaxy in the Universe, and it has long been regarded as a benchmark and ideal laboratory for understanding galaxy evolution. Recent studies compared the Milky Way with its analogues from IFS surveys and revealed common structures such as the B/P bulge, thin and thick disks, etc. This presents a unique opportunity to link Galactic and extragalactic studies to understand galaxy evolution. However, high stellar density regions like the Galactic bulge and the core of globular clusters have not been fully explored but they are essential in the Galactic evolution. This is due to the fiber collision issues of fiber-fed multi-object spectrographs and extreme extinction. Furthermore, direct comparisons of Galactic and extragalactic observations are marred by differences in using individual stars vs. stellar populations and methods of measuring galaxy properties. It is difficult to identify whether the differences between the Milky Way and other galaxies are due to systematic offsets or different evolution processes. This thesis addresses these difficulties using the MUSE integral-field spectrograph. We develop a novel method to measure stellar chemical abundances of individual stars from MUSE. This method is then used to study the age distribution and chemical evolution of MSTO-SGB stars in low-extinction regions of the Galactic center. Our results agree with previous studies but are obtained more efficiently. We further present a tool to generate mock MUSE observations of the Milky Way using GCE models and spectral templates for unbiased comparisons with external galaxies. We use mock data to investigate the reliability of a broadly used tool PPXF in measuring external galaxy properties and explore the impact of dust on these results. This research facilitates a deeper understanding of critical Galactic structures such as the bulge and bridges the gap between Galactic and extragalactic studies for understanding galaxy evolution