Sökning: "escape fraction"

Visar resultat 1 - 5 av 20 avhandlingar innehållade orden escape fraction.

  1. 1. 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

  3. 2. Low-Energy Ion Escape from the Terrestrial Polar Regions

    Författare :Erik Engwall; Anders I. Eriksson; Mats André; Thomas Moore; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; space physics; ion outflow; polar wind; auroral upflows; atmospheric escape; magnetotail lobes; spacecraft wake; electric field measurements; Geocosmophysics and plasma physics; Geokosmofysik och plasmafysik; Space and Plasma Physics; rymd- och plasmafysik;

    Sammanfattning : The contemporary terrestrial atmosphere loses matter at a rate of around 100,000 tons per year. A major fraction of the net mass loss is constituted by ions, mainly H+ and O+, which escape from the Earth’s ionosphere in the polar regions. LÄS MER

  4. 3. How ISM properties drive Lyman Continuum Escape

    Författare :Johannes Puschnig; Matthew Hayes; Göran Östlin; Rahman Amanullah; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astrophysics; Cosmology; Extragalactics; Reionization; Lyman Continuum; Interstellar Medium; ISM; Tololo 1247-232; Astronomy; astronomi;

    Sammanfattning : The thesis introduces physical processes that are at work in astrophysical plasmas and reviews the current state of research related to the emission of ionizing photons, i.e. Lyman continuum (LyC). Star forming galaxies and active galactic nuclei are discussed as sources of LyC. LÄS MER

  5. 4. Observing Lyman alpha emitters - How does Lyman alpha escape from galaxies?

    Författare :Andreas Sandberg; Göran Östlin; Lucia Guaita; Matthew Hayes; Caryl Gronwall; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; astronomi;

    Sammanfattning : The Lyman alpha (Lyα) emission line has grown to become one of the most successful tools for finding galaxies at high redshift. At redshifts corresponding to the early cosmic times of reionization and primeval galaxy formation, the wavelength of Lyα is still accessible with ground-based facilities. LÄS MER

  7. 5. Recognition by and escape from CD8+ T cell immune surveillance in cancer bearing hosts

    Författare :Koji Kono; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :;

    Sammanfattning : CD8+ T cells ( TCD8+ ) can specifically recognize tumor cells through MHC class I molecules associated with peptides that are 8-l0 amino acid residues long. In recent years, a number of tumor-associated antigens, or their epitopes, have been identified and characterized with the advent of new methods in molecular biology and in peptide isolation. LÄS MER