Sökning: "techniques: photometric"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden techniques: photometric.

  1. 1. Solar Type Stars as Calibrators : A Photometric and Spectroscopic Study on the Atmospheric Properties of Late-type Stars

    Författare :Anna Önehag; Ulrike Heiter; Andreas Korn; Bengt Gustafsson; Frank Grundahl; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; stars: atmospheres; stars: late-type; techniques: photometric; stars: abundances; techniques: spectroscopic; Astronomy; Astronomi;

    Sammanfattning : Detailed knowledge of solar-type stars is essential in the understanding of the evolutionary past, presence and future of the Sun as well as the formation of its planetary system. Moreover, solar-type stars are of key significance for the study of the evolution of the Galaxy. The ages of solar-type stars map the full galactic evolution. LÄS MER

  3. 2. Photometry of Resolved Stellar Populations in Local Group Galaxies

    Författare :Daniel Faria; Astronomi - Genomgår omorganisation; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomi; Astronomy; Local Group; Galaxy: halo; Galaxies: dwarf; Galaxy: stellar content; Galaxies: photometry; Techniques: photometric; Stars: fundamental parameters;

    Sammanfattning : This thesis presents results from two projects using photometric observations to investigate stellar populations in Local Group galaxies. In the first project, Strömgren photometry is used to study stellar populations in dwarf spheroidal galaxies. LÄS MER

  4. 3. 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

  5. 4. The Frequency of Supernovae in the Early Universe

    Författare :Jens Melinder; Claes Fransson; Enrico Cappellaro; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; supernovae; supernova typing; supernova rates; photometric redshifts; Lyman Break Galaxies; Astronomy; Astronomi; Astronomy; astronomi;

    Sammanfattning : Supernovae are cosmic explosions of cataclysmic proportion that signify the death of a star. While being interesting phenomena in their own right, their brightness also make them excellent probes of the early universe. Depending on the type of the progenitor star and the origin of the explosion different subjects can be investigated. LÄS MER

  7. 5. Crowded Field Photometry and Luminosity Function Analysis as Probes of Galactic Evolution

    Författare :Ralph Snel; Astronomi - Genomgår omorganisation; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; observational; Methods: data analysis; statistical - Techniques: photometric - Stars: luminosity function; imaging; evolution - Galaxies: stellar content; mass function; space research; cosmic chemistry; Astronomi; rymdvetenskap; kosmisk kemi; Fysicumarkivet A:1998:Snel;

    Sammanfattning : Crowded field photometry is a powerful method to investigate stellar evolutionary processes in astrophysically interesting regions such as nearby external galaxies and globular cluster cores. While detectors are approaching the physical limits for photon detection, data analysis methods for crowded stellar fields are not yet equally sophisticated. LÄS MER