Sökning: "dwarf irregular galaxies"

Hittade 4 avhandlingar innehållade orden dwarf irregular galaxies.

1. 1. A study of possible chemical inhomogeneities of dwarf irregular galaxies and the influence on the Z-L relationship

   Författare :Ana Maria Hidalgo-Gámez; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; dwarf irregular galaxies; chemical abundances; metallicity-luminosity relationship; individual galaxies: NGC 6822; IC 4662; IC 10; ESO 245-G05; NGC 1569; IC 5152; DDO 53 and DDO 190; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; astronomi; Astronomy;

   Sammanfattning : A study on the chemical abundances of dwarf irregular galaxies (dI's) is presented in this work. This type of galaxies have typically low metallicity. First of all, a definition of dI is proposed, in order to obtain a homogeneous group of targets. LÄS MER

3. 2. On the Escape of Lyman Radiation from Local Galaxies

   Författare :Elisabet Leitet; Nils Bergvall; Erik Zackrisson; Bengt Gustafsson; Duilia F. De Mello; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Galaxies; starbursts; spiral galaxies; Lyman continuum; Lyman alpha; leakage; cosmic reionization; escape fraction; Astronomy; Astronomi;

   Sammanfattning : Cosmic reionization was most likely initiated by star forming dwarf galaxies. Little is known about the physical mechanisms allowing ionizing Lyman continuum (LyC) photons to escape from galaxies, but to learn more we can study local galaxies in detail. LÄS MER

4. 3. The Kinematics of Blue Compact Galaxies - Gas and Stars

   Författare :Thomas Marquart; Uppsala universitet; []
   Nyckelord :;

   Sammanfattning : Blue Compact Galaxies (BCGs) are intensely star forming, gas-rich systems and their light is dominated by a young stellar population and nebular emission. Their irregular morphology suggests dwarf galaxy mergers as cause for the onset of the burst in star formation. LÄS MER

5. 4. Stochastic Chemical Evolution : A Study of Scatter in Relative Elemental Abundances in Extremely Metal-poor Stars

   Författare :Torgny Karlsson; Bengt Gustafsson; Mike Edmunds; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; nucleosynthesis; chemical evolution; Galactic evolution; supernovae; chemical abundances; Population II stars; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik;

   Sammanfattning : Chemical evolution addresses the problem of the formation of the chemical elements and their evolution throughout the history of the universe. This thesis discusses in particular the chemical evolution in the young universe and what we may learn from the observations of the oldest stars. LÄS MER