Sökning: "astronomi"

Visar resultat 6 - 10 av 644 avhandlingar innehållade ordet astronomi.

1. 6. Asymptotic Giant Branch stars viewed up-close and far-off : The physics, chemistry, and evolution of their circumstellar envelopes

   Författare :Matthias Maercker; Hans Olofsson; Fredrik L. Schöier; Laurentius B. F. M. Waters; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; AGB stars; evolution; mass-loss; abundances; Astronomy; Astronomi; Astronomy; astronomi;

   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

3. 7. The Frequency of Supernovae in the Early Universe

   Författare :Jens Melinder; Claes Fransson; Enrico Cappellaro; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; supernovae; supernova typing; supernova rates; photometric redshifts; Lyman Break Galaxies; Astronomy; Astronomi; Astronomy; astronomi;

   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

4. 8. Distant supernovae and galaxies in the Stockholm VIMOS Supernova Survey

   Författare :Laia Mencia Trinchant; Göran Östlin; Duilia F de Mello; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; imaging surveys; photometric redshfits; Lyman Break galaxies; supernova typing; supernova rates; supernova host galaxies; Astronomy; Astronomi; Astronomy; astronomi;

   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

5. 9. Deep photometry of galaxies : to see or not to see /Magnus Näslund

   Författare :Magnus Näslund; Nils Bergvall; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; Astronomi; Astronomy; astronomi;

   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

7. 10. Investigating the Dark Universe through Gravitational Lensing

   Författare :Teresa Riehm; Ariel Goobar; Edvard Mörtsell; Erik Zackrisson; Joachim Wambsganss; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; cosmology; gravitational lensing; dark matter; galaxies; galaxy clusters; Astronomy; Astronomi; Astronomy; astronomi;

   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