Sökning: "galactic evolution"

Visar resultat 26 - 30 av 48 avhandlingar innehållade orden galactic evolution.

  1. 26. An ALMA perspective on high-redshift galaxy evolution

    Författare :Kiana Kade; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The processes governing the growth and evolution of high-redshift massive galaxies have long been a subject of intense investigations. Studies of the cosmic star-formation rate density have shown a peak at z ∼ 2 − 3, demonstrating the distinct need to understand the mechanisms by which galaxies acquired the fuel necessary to ignite such intense star formation. LÄS MER

  3. 27. The cosmic origin of fluorine and sulphur: Infrared spectroscopic studies of red giants

    Författare :Henrik Jönsson; Astronomi - Genomgår omorganisation; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemical evolution; near-infrared and mid-infrared spectroscopy; stellar abundances;

    Sammanfattning : Disregarding the small primordial traces of the lightest elements, all metals have been formed in stellar processes, which means that the relative amount of metals in the Universe increases for every stellar generation. This build-up of elements is called chemical evolution and might be used both to constrain stellar models as well as understanding the formation and evolution of stellar populations. LÄS MER

  4. 28. The nature of stars with a common origin: clues from metallicity, elemental abundances, and kinematics

    Författare :Cheng Liu; Astronomi - Genomgår omorganisation; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Stars: abundances; Galaxy: evolution; Galaxy: solar neighbourhood; Galaxy: bulge; Galaxy: globular clusters;

    Sammanfattning : Most of field stars originate from dissolved star clusters. If the gas cloud is well mixed the stars in the cluster are expected to be chemically homogenous. LÄS MER

  5. 29. Searches for Particle Dark Matter : Dark stars, dark galaxies, dark halos and global supersymmetric fits

    Författare :Pat Scott; Joakim Edsjö; Lars Bergström; Jan Conrad; Dan Hooper; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; dark matter; supersymmetry; gamma rays; dwarf galaxies; stellar evolution; cosmological perturbations; phase transitions; statistical techniques; Astroparticle physics; Astropartikelfysik; Astroparticle physics; Astropartikelfysik; Cosmology; Kosmologi; Elementary particle physics; Elementarpartikelfysik; Computational physics; Beräkningsfysik; Formation and development of stars; Stjärnors bildning och utveckling; High energy astrophysics; Högenergiastrofysik; teoretisk fysik; Theoretical Physics;

    Sammanfattning : The identity of dark matter is one of the key outstanding problems in both particle and astrophysics. In this thesis, I describe a number of complementary searches for particle dark matter. LÄS MER

  7. 30. X-ray variability in Galactic high-mass black hole binaries

    Författare :Magnus Axelsson; Stefan Larsson; Chris Done; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Accretion; high-energy astrophysics; temporal variability; X-ray binaries; Astronomy and astrophysics; Astronomi och astrofysik; Astronomy; astronomi;

    Sammanfattning : The stars of the night sky can to the naked eye appear to be steady and unchanging, apart from the twinkling created by air moving in the atmosphere. However, when viewed in X-rays, the sky is far from constant, with detectable changes occurring on very short timescales.Black hole X-ray binaries are strong sources of X-rays. LÄS MER