Sökning: "Galaxy: halo"

Visar resultat 11 - 15 av 21 avhandlingar innehållade orden Galaxy: halo.

1. 11. Dissipative formation of galaxies in hierarchical cosmology

   Författare :John Hultman; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; merical methods; hydrodynamics; galaxies: formation; galaxies: elliptical; galaxies: structure; star formation; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; Theoretical Astrophysics; teoretisk astrofysik;

   Sammanfattning : A description and detailed tests of a numerical code for simulations of galaxy formation is presented. The dynamics is followed with fully adaptive and Lagrangian Smooth Particle Hydrodynamics (SPH) combined with a gravitational tree method. The severe numerical problem of sub-resolution clustering is solved by merging of gas particles. LÄS MER

3. 12. A Dark Matter Search with AMANDA : Limits on the Muon Flux from Neutralino Annihilations at the Centre of the Earth with 1997-99 Data

   Författare :Patrik Ekström; Per Olof Hulth; Lee Thompson; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Elementary particle physics; Elementarpartikelfysik;

   Sammanfattning : The nature of the dark matter in the Universe is one of the greatest mysteries in modern astronomy. The neutralino is a nonbaryonic dark matter candidate in minimal supersymmetric extensions to the standard model of particle physics. LÄS MER

4. 13. Dark Matter Phenomenology in Astrophysical Systems

   Författare :Stefan Clementz; Mattias Blennow; Kai Schmidt-Hoberg; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fysik; Physics;

   Sammanfattning : There is now a great deal of evidence in support of the existence of a large amount of unseen gravitational mass, commonly called dark matter, from observations in astrophysical systems of sizes ranging from that of dwarf galaxies to the scale of the entire Universe. One of the most promising explanations for this unseen mass is that it consists of a species of unobserved elementary particles. LÄS MER

5. 14. A search for neutralino dark matter with the AMANDA-B10 detector

   Författare :Eva Dalberg; Yves Sacquin; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; fysik;

   Sammanfattning : If supersymmetric particles in the form of neutralinos are part of the dark matter halo in our Galaxy, they can accumulate gravitationally in the center of the Earth and pair-wise annihilate therein. Such annihilations can be observed as an excess signal of vertical up-moving neutrino induced muon tracks in a neutrino detector like AMANDA. LÄS MER

7. 15. Transfer of Angular Momentum in Astrophysical Discs

   Författare :Mattias Wahde; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : In this thesis a study of astrophysical discs, with emphasis on galactic discs, is presented. The frictional force acting on a small satellite galaxy, moving on a co-planar circular orbit in a galactic disc, is shown to be only weakly dependent on the velocity dispersion and the self-gravity of the disc. LÄS MER