Sökning: "cosmic reionization"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden cosmic reionization.

  1. 1. Simulations of Cosmic Reionization : Shapes & Sizes of H II regions around Galaxies and Quasars

    Författare :Martina M. Friedrich; Garrelt Mellema; Jonathan Pritchard; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; astronomi;

    Sammanfattning : After the era of recombination, roughly 360 000 years after the big bang (redshift 1100), the universe was neutral, continued to expand and eventually the first gravitationally collapsed structures capable of forming stars, formed. Observations show that approximately 1 billion years later (redshift 6), the Universe had become highly ionized. LÄS MER

  2. 2. Galaxies in the epoch of reionization : Investigating the high-redshift galaxy population through simulations and observations

    Författare :Christian Binggeli; Erik Zackrisson; Sofia Ramstedt; Martin Sahlén; Stephen Wilkins; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; galaxies: high-redshift; galaxies: ISM; galaxies: evolution; reionization; Lyman continuum; Astronomy; Astronomi;

    Sammanfattning : The cosmic reionization is the last major gas phase transition in cosmic history, yet it remains poorly understood. Current constraints indicate that early star-forming galaxies drove the reionization process through producing and releasing large numbers of ionizing photons into the intergalactic medium. LÄS MER

  3. 3. Molecular gas and ionizing radiation in star-forming galaxies

    Författare :Johannes Puschnig; Matthew Hayes; Göran Östlin; Amélie Saintonge; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; astrophysics; galaxies; star formation; starburst; interstellar medium; Lyman continuum; Lyman alpha; reionization; gravitational instability; molecular gas; clump formation; Astronomy; astronomi;

    Sammanfattning : In cosmic history, some of the major changes such as reionization were driven by baryons (i.e. the stars and gas in galaxies), despite the fact that they contribute only few percent to the total mass-energy budget in the Universe. LÄS MER

  4. 4. 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. 5. 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