Sökning: "Galaxy: evolution"

Visar resultat 21 - 25 av 74 avhandlingar innehållade orden Galaxy: evolution.

  1. 21. Using Lyα to illuminate the circumgalactic medium and the Epoch of Reionization : Lessons from low redshift

    Författare :Axel Runnholm; Matthew J. Hayes; Ross McLure; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Lyman alpha galaxies; Starburst galaxies; Galaxy evolution; Epoch of Reionization; Circumgalactic medium; Astronomy; astronomi;

    Sammanfattning : The field of extragalactic astronomy is progressing rapidly but there is still much to understand and many questions that remain open. During recent years the Lyα emission line has come to the fore as a potentially very powerful astrophysical tool and is now routinely used to find galaxies at the very highest redshifts. LÄS MER

  3. 22. Star Formation and feedback at key physical scales for galaxy evolution

    Författare :Lorenza Della Bruna; Angela Adamo; Göran Östlin; Monica Relaño Pastor; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Galaxies; Star Formation; Stellar Feedback; HII regions; ISM; Astronomy; astronomi;

    Sammanfattning : Feedback from young, massive stars plays an essential role in the self-regulation of star formation in galaxies, and in shaping the galaxies' global properties. This phenomenon originates at small scales, surrounding the stars, but has been observed to be effective up to galactic-wide scales. LÄS MER

  4. 23. On the Winds of Carbon Stars and the Origin of Carbon : A Theoretical Study

    Författare :Lars Mattsson; Susanne Höfner; Nils Bergvall; Kjell Olofsson; Martin Groenewegen; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; AGB stars; carbon stars; mass loss; stellar winds; circumstellar matter; cosmic dust; stellar evolution; nucleosynthesis; galactic chemical evolution; Astronomy and astrophysics; Astronomi och astrofysik; Astronomy; Astronomi; Fysik; Physics;

    Sammanfattning : Carbon is the basis for life, as we know it, but its origin is still largely unclear. Carbon-rich Asymptotic Giant Branch (AGB) stars (carbon stars) play an important rôle in the cosmic matter cycle and may contribute most of the carbon in the Galaxy. LÄS MER

  5. 24. On the Abundances of Li, Be and O in Metal-Poor Stars in the Galaxy

    Författare :Ana Elia García Pérez; Martin Asplund; Bengt Gustafsson; Francesca Primas; Beatriz Barbuy; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; galactic evolution; stellar abundances; stellar atmospheres; spectral line formation; stellar mixing; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik;

    Sammanfattning : Stellar atmospheres constitute excellent environments to study the chemical evolution of our Galaxy. The chemical composition of these atmospheres reflects the composition of the gas from where these stars were born. LÄS MER

  7. 25. Molecular observations of obscured galaxy nuclei

    Författare :Niklas Falstad; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Galaxies: nuclei; Galaxies: ISM; Infrared: galaxies; ISM: Molecules; Submillimeter: galaxies;

    Sammanfattning : It is becoming evident that some (ultra)luminous infrared galaxies ((U)LIRGs) contain compact obscured nuclei (CONs) where luminosities in excess of 10^9 L☉  emerge from inside dusty regions smaller than 100 pc in diameter. Due to the obscured nature of these objects, their inner regions are hidden from examination using optical or infrared lines. LÄS MER