Sökning: "dwarf"

Visar resultat 1 - 5 av 75 avhandlingar innehållade ordet dwarf.

1. 1. Star-forming Dwarf Galaxies : Internal motions and evolution

   Författare :Thomas Marquart; Nils Bergvall; Janice Lee; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Galaxy; Galaxies; Dynamics; Kinematics; Starburst; Dwarf Galaxies; Blue Compact Galaxies; Star Formation; Galaxy mergers; 3D-Spectroscopy; Spectroscopy; Astronomy; Astronomi;

   Sammanfattning : The study of dwarf galaxies is important in order to better understand the physics of the young universe and how larger galaxies form and evolve. In this work we focus on Blue Compact Galaxies (BCGs) which havemuch enhanced star formation (starbursts), causing blue colours and strong emission line spectra. LÄS MER

3. 2. Dark matter signal normalisation for dwarf spheroidal galaxies : A frequentist analysis of stellar kinematics for indirect Dark Matter searches

   Författare :Andrea Chiappo; Jan Conrad; Piero Ullio; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; dark matter; dwarf galaxies; kinematics and dynamics of galaxies; fysik; Physics;

   Sammanfattning : Indirect detection strategies of Dark Matter (DM) entail searching for signals of DM annihilation or decay, typically in the form of excess positrons or high-energy photons above the astrophysical background, originating from (inferred) DM-rich environments. Due to their characteristics, dwarf spheroidal satellite galaxies (dSphs) of the Milky Way are considered very promising targets for indirect particle DM identification. LÄS MER

4. 3. Epidemiology of wheat dwarf virus

   Författare :Elham Yazdkhasti; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
   Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES;

   Sammanfattning : In Sweden and many other parts of Europe, wheat dwarf is one of the most important diseases induced by a plant-infecting virus. Wheat dwarf disease is caused by wheat dwarf virus (WDV), transmitted by the leafhopper Psammotettix alienus. LÄS MER

5. 4. On the origin and evolution of blue compact galaxies

   Författare :Göran A. Östlin; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; galaxies - compact; formation; evolution; starburst; interactions; dwarf; photometry; kinematics and dynamics; low surface brightness galaxies; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; astronomi; Astronomy;

   Sammanfattning : This thesis is focused on the origin and evolution of blue compact galaxies (BCGs). BCGs are low mass galaxies characterised by blue colours, low chemical abundances and high star formation rates. The gas consumtion time scale is considerable shorter than the age of the universe and thus the high star formation rate must be transient. LÄS MER

7. 5. Future stratospheric ozone depletion will affect a subarctic dwarf shrub ecosystem

   Författare :Ulf Johanson; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Vaccinium; UVB; subarctic; shoot growth; ozone depletion; leaf thickness; irradiation system; heath ecosystem; Empetrum; dwarf shrubs; Calamagrostis; decomposition; Physiological biophysics; Växtfysiologi;

   Sammanfattning : The stratospheric ozone depletion and the concomitant increase in ultraviolet-B (UV-B, 280-320 nm) radiation is of global concern due to the effects of UV-B on living organisms. To investigate the effects of increased levels of UV-B, a field irradiation system was established at a subarctic dwarf shrub heath in Northern Sweden (68 °N). LÄS MER