Sökning: "NATURAL SCIENCES Physics Astronomy and astrophysics Cosmology"

Visar resultat 21 - 25 av 139 avhandlingar innehållade orden NATURAL SCIENCES Physics Astronomy and astrophysics Cosmology.

1. 21. Experimental and Computational Atomic Spectroscopy for Astrophysics : Oscillator strengths and lifetimes for Mg I, Si I, Si II, Sc I, and Sc II

   Författare :Asli Pehlivan Rhodin; Astronomi - Genomgår omorganisation; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Atomic Data; Astrophysics - Solar and Stellar Astrophysics;

   Sammanfattning : Atomic data such as oscillator strengths and wavelengths are important for astrophysical applications as they have a crucial role in determining abundances of specific elements in a star, a galaxy, or any object emitting radiation in the space. Stars in the Galaxy mostly keep the composition of the interstellar gas from which they were formed, therefore studying stellar abundances helps us understand how the Milky Way was formed and how it evolved. LÄS MER

3. 22. Cosmological Models and Singularities in General Relativity

   Författare :Patrik Sandin; Claes Uggla; Alan Coley; Karlstads universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; general relativity; Bianchi cosmology; singularities; dynamical systems; Fuchsian methods; Hamiltonian methods; Theory of relativity; gravitation; Relativitetsteori; gravitation; Physics; Fysik;

   Sammanfattning : This is a thesis on general relativity. It analyzes dynamical properties of Einstein's field equations in cosmology and in the vicinity of spacetime singularities in a number of different situations. LÄS MER

4. 23. Observations of distant supernovae and cosmological implications

   Författare :Rahman Amanullah; Ariel Goobar; Adam Riess; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; cosmological parameters; cosmology; astro physics; supernovae; type Ia supernova; Cosmology; Kosmologi;

   Sammanfattning : Type Ia supernovae can be used as distance indicators for probing the expansion history of the Universe. The method has proved to be an efficient tool in cosmology and played a decisive role in the discovery of a yet unknown energy form, dark energy, that drives the accelerated expansion of the Universe. LÄS MER

5. 24. Studies of dark matter annihilation and production in the Universe

   Författare :Carl Niblaeus; Joakim Edsjö; Riccardo Catena; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; dark matter; neutrinos; astroparticle physics; indirect detection; teoretisk fysik; Theoretical Physics;

   Sammanfattning : In this PhD thesis we investigate various aspects of particle dark matter. The proper identification of dark matter developed during the second half of the twentieth century to become one of the biggest endeavours in modern physics and astronomy. LÄS MER

7. 25. Dispersive and polarimetric properties of waves in space plasma

   Författare :Jan Bergman; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; Space Physics; rymdfysik;

   Sammanfattning : Various aspects regarding dispersive and polarimetric properties of waves in space plasma are discussed from a theoretical viewpoint, which is extended to include numerical as well as experimental studies. From a more technical viewpoint, two scientific instruments are described. LÄS MER