Sökning: "galactic evolution"
Visar resultat 21 - 25 av 48 avhandlingar innehållade orden galactic evolution.
21. Observational Studies of the Chemical Evolution in the Galactic Thin and Thick Disks
Sammanfattning : The origin and evolution of the thin and thick disks in the Galaxy have been studied by means of detailed stellar abundances. High-resolution spectra of 102 F and G dwarf stars have been obtained with the spectrographs on the ESO 3.6-m and ESO 1. LÄS MER
22. High-redshift active galactic nuclei and their environment
Sammanfattning : In order to understand the formation and evolution of local massive galaxies and to reveal the processes that engineered the tight correlations found between their supermassive black hole (SMBH) mass and bulge mass or velocity dispersion, the study of powerful, high-redshift active galactic nuclei (AGNs) and their environment is crucial. AGNs are luminous targets providing important clues to galaxy evolution, as their central SMBH is growing at high rates, which opens the opportunity to unfold how the growth of the black hole influences the growth of its host galaxy. LÄS MER
23. Star clusters as engines of galaxy evolution
Sammanfattning : Feedback in star forming galaxies is the key process that regulates how many stars form given the available gas reservoir. The radiation, energy and momentum released by the stellar activity and the active galactic nuclei change the physical properties of the gas in the galaxy such as the ionisation state, the density and the kinematics. LÄS MER
24. Star clusters as engines of galaxy evolution
Sammanfattning : Stars form and live in hierarchical structures such as star clusters on the smallest scales up to groups of galaxies on the largest scales. The role of young and massive star clusters in the evolution of the host galaxies is one of the most active fields of research in modern astronomy. LÄS MER
25. On the Chemical Composition of Metal-Poor Stars : Impact of Stellar Granulation and Departures from Local Thermodynamic Equilibrium on the Formation of Spectral Lines
Sammanfattning : The information about the chemical compositions of stars is encoded in their spectra. Accurate determinations of these compositions are crucial for our understanding of stellar nucleosynthesis and Galactic chemical evolution. LÄS MER