Search for dissertations about: "Observational constraints"

Showing result 1 - 5 of 34 swedish dissertations containing the words Observational constraints.

  2. 1. Was Einstein Wrong? : Theoretical and observational constraints on massive gravity

    Author : Marcus Högås; Edvard Mörtsell; David Mota; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Gravity; Massive gravity; Bimetric gravity; Cosmology; Gravitational collapse; Gravitational waves; Observational constraints; Theoretical Physics; teoretisk fysik;

    Abstract : For more than a century, Einstein's theory of general relativity has described gravitational phenomena with astonishing precision. However, for the theory to fit observations we need to add two elusive substances: dark energy and dark matter. Together they add up to 95% of the energy budget of the Universe. READ MORE

  4. 2. Exploring the Chemical Evolution of Globular Clusters and their Stars : Observational Constraints on Atomic Diffusion and Cluster Pollution in NGC 6752 and M4

    Author : Pieter Gruyters; Andreas Korn; Piercarlo Bonifacio; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; stars: abundances – stars: atmospheres – stars: fundamental parameters – globular clusters: individual: NGC 6752 and M4 – techniques: spectroscopic; Astronomy with specialization in Astrophysics; Astronomi med intiktning mot astrofysik;

    Abstract : Through the cosmic matter cycle, the chemical evolution of the Milky Way is imprinted in the elemental abundance patterns of late-type stars (spectral types F to K). Due to their long lifetimes ( 1 Hubble time), these stars are of particular importance when it comes to studying the build-up of elements during the early times of our Galaxy. READ MORE

  5. 3. Supersymmetry vis-à-vis Observation : Dark Matter Constraints, Global Fits and Statistical Issues

    Author : Yashar Akrami; Joakim Edsjö; Lars Bergström; Roberto Trotta; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; supersymmetry; cosmology of theories beyond the Standard Model; dark matter; gamma rays; dwarf galaxies; direct detection; statistical techniques; scanning algorithms; genetic algorithms; statistical coverage; Astroparticle physics; Astropartikelfysik; Cosmology; Kosmologi; Astroparticle physics; Astropartikelfysik; teoretisk fysik; Theoretical Physics;

    Abstract : Weak-scale supersymmetry is one of the most favoured theories beyond the Standard Model of particle physics that elegantly solves various theoretical and observational problems in both particle physics and cosmology. In this thesis, I describe the theoretical foundations of supersymmetry, issues that it can address and concrete supersymmetric models that are widely used in phenomenological studies. READ MORE

  6. 4. Treeline dynamics in short and long term perspectives : observational and historical evidence from the southern Swedish Scandes

    Author : Lisa Öberg; Bengt-Gunnar Jonsson; Leif Kullman; Ulf Segerström; Mittuniversitetet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Betula pubescens ssp. czerepanovii; Picea abies; Pinus sylvestris; climate change; monitoring; treeline advance; clones; megafossils; immigration; Holocene; cryptic refugia; Swedish Scandes; Terrestrial ecology; Terrestrisk ekologi;

    Abstract : Against the background of past, recent and future climate change, the present thesis addresses elevational shifts of alpine treelines in the Swedish Scandes. By definition, treeline refers to the elevation (m a.s.l. READ MORE

  7. 5. Observational Studies of the Chemical Evolution in the Galactic Thin and Thick Disks

    Author : Thomas Bensby; Astronomi - Genomgår omorganisation; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy; Astronomi; Fysicumarkivet A:2004:Bensby;

    Abstract : 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. READ MORE