Sökning: "Astronomi"
Visar resultat 6 - 10 av 644 avhandlingar innehållade ordet Astronomi.
6. Asymptotic Giant Branch stars viewed up-close and far-off : The physics, chemistry, and evolution of their circumstellar envelopes
Sammanfattning : The asymptotic giant branch (AGB) is the last stage of stellar evolution for stars with masses between 0.8-8 M(sun). This phase is characterised by an intense mass loss, which builds up a circumstellar envelope of dust and gas(CSE). It is through this process that the AGB stars contribute to the chemical evolution of galaxies. LÄS MER
7. The Frequency of Supernovae in the Early Universe
Sammanfattning : Supernovae are cosmic explosions of cataclysmic proportion that signify the death of a star. While being interesting phenomena in their own right, their brightness also make them excellent probes of the early universe. Depending on the type of the progenitor star and the origin of the explosion different subjects can be investigated. LÄS MER
8. Distant supernovae and galaxies in the Stockholm VIMOS Supernova Survey
Sammanfattning : Multi colour imaging surveys help astronomers to find galaxies and clusters,and to gain insights on their physical properties and evolution. In this thesis, I present the Stockholm VIMOS Supernova Survey (SVISS), where the ELAIS-S field was observed with VIMOS UBVRI broad-band optical bands over a period of 5 years. LÄS MER
9. Deep photometry of galaxies : to see or not to see /Magnus Näslund
Sammanfattning : The edge-on spiral galaxy NGC 4565 and the distant galaxy cluster MS2255.7+2039 have been studied at optical wavelengths with deep photometry using the 2.56 m Nordic Optical Telescope on La Palma.By careful data reductions we traced the surface brightness of NGC 4565 to faint levels. LÄS MER
10. Investigating the Dark Universe through Gravitational Lensing
Sammanfattning : A variety of precision observations suggest that the present universe is dominated by some unknown components, the so-called dark matter and dark energy. The distribution and properties of these components are the focus of modern cosmology and we are only beginning to understand them. LÄS MER