Search for dissertations about: "Galaxy : formation"
Showing result 21 - 25 of 75 swedish dissertations containing the words Galaxy : formation.
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21. Observations of nearby Galaxy Clusters with the Fermi Large Area Telescope : Towards the first Gamma Rays from Clusters
Abstract : Galaxy clusters are the most massive bound systems known in the Universe and are believed to have formed through large scale structure formation. They host relativistic cosmic-ray (CR) populations and are gravitationally bound by large amounts of Dark Matter (DM), both providing conditions in which high-energy gamma rays may be produced either via CR interactions with the intracluster medium or through the annihilation or decay of DM particles. READ MORE
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22. Active Galactic Nuclei in galaxy surveys : Empirical paths to the fiery hearts of cosmic beasts
Abstract : Some galaxies emit excessive amounts of light from their centers, caused by accretion of gas onto super-massive black holes (SMBH). These galactic cores are often referred to as Active Galactic Nuclei (AGN) and they come in many different forms, distinguishable by their emission properties. READ MORE
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23. Clues to galaxy evolution from spectroscopic observations of Galactic centre stars
Abstract : In this work we present results from spectroscopic observations of Galactic centre stars. High resolution stellar spectroscopy can be used to determine accurate stellar metallicities and abundances. Observing stars in the Galactic centre is challenging due to extreme extinction. READ MORE
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24. Search for lensed supernovae behind the galaxy cluster Abell 1689
Abstract : Distant supernovae probe the history of cosmic expansion and star formation, and provide important information on their progenitor models. Investigation of supernovae type Ia for are needed to reveal any evolution in their intrinsic properties, and thus their utility as existing distance indicators. READ MORE
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25. Determination of stellar ages and star formation histories - a Bayesian approach With an application to nearby F and G stars
Abstract : In order to understand the formation and evolution of the Galaxy it is imperative to know when different components formed. This means at the most basic level that we need to know the ages of stars. The present work demonstrates the many problems inherent in determining the ages of stars through comparison with stellar evolutionary models. READ MORE