Sökning: "Erik Zackrisson"

Visar resultat 1 - 5 av 10 avhandlingar innehållade orden Erik Zackrisson.

  1. 1. Gravitational lensing as a probe of the first stars and galaxies

    Författare :Claes-Erik Rydberg; Erik Zackrisson; Lise Christensen; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; stars: Population III; first stars; Galaxies: high-redshift; Galaxies: Population III; dark ages; reionization; techniques: photometric; Astronomy; astronomi;

    Sammanfattning : This thesis investigates the potential for detection and identification of primordial stars, galaxies, and supernovae at high redshift.Simulations indicate that the first Population III stars should appear in minihalos of mass M = 105-106 Msol at z ≈ 10-30. LÄS MER

  2. 2. Quasars and Low Surface Brightness Galaxies as Probes of Dark Matter

    Författare :Erik Zackrisson; Nils Bergvall; Kjell Olofsson; Julianne Dalcanton; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; Cosmology: dark matter; gravitational lensing; quasars: general; quasars: redshift; galaxies: halos; galaxies: formation; galaxies: stellar content; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik;

    Sammanfattning : Most of the matter in the Universe appears to be in some form which does not emit or absorb light. While evidence for the existence of this dark matter has accumulated over the last seventy years, its nature remains elusive. LÄS MER

  3. 3. Super Star Clusters in Blue Compact Galaxies : Evidence for a near-infrared flux excess and properties of the starburst phase

    Författare :Angela Adamo; Göran Östlin; Erik Zackrisson; Richard de Grjis; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; starburst galaxy-extragalactic star clusters-dwarf merger; Astronomy and astrophysics; Astronomi och astrofysik; Astronomy; astronomi;

    Sammanfattning : Luminous Blue compact galaxies (BCGs) are metal-poor actively star-forming systems, characterised by bright ultraviolet and blue luminosities. Hubble Space Telescope high-resolution data have revealed that the luminous star-forming knots in these galaxies are composed of hundreds of young massive star clusters. LÄS MER

  4. 4. 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

  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