Search for dissertations about: "Astronomy"

Showing result 11 - 15 of 540 swedish dissertations containing the word Astronomy.

  2. 11. Spectral and Temporal Studies of Gamma-Ray Bursts

    Author : Luis Borgonovo; Claes-Ingvar Björnsson; Jerry Fishman; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy and astrophysics; Astronomi och astrofysik; Astronomy; astronomi;

    Abstract : Gamma-ray bursts (GRBs) are sporadic flashes of light observed primarily in the gamma-ray band. Being the brightest explosions in the Universe since its birth, they are at present also the furthest astronomical sources detected. READ MORE

  4. 12. Radio waves in the ionosphere : Propagation, generation and detection

    Author : Tobia Carozzi; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; Space Physics; rymdfysik;

    Abstract : We discuss various topics concerning the propagation, generation, and detec-tionof high-frequency (HF) radio waves in the Earth's ionosphere. With re-gardsto propagation, we derive a full wave Hamiltonian and a polarization evo-lutionequation for electromagnetic waves in a cold, stratified magnetoplasma. READ MORE

  5. 13. Thermophysical Modelling and Mechanical Stability of Cometary Nuclei

    Author : Björn Davidsson; Dina Prialnik; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy; Comets; Tidal physics; Light scattering; Radiative transfer; Thermophysics; Gas kinetics; Non-gravitational forces; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; Theoretical Astrophysics; teoretisk astrofysik;

    Abstract : Comets are the most primordial and least evolved bodies in the Solar System. As such, they are unique sources of information regarding the early history of the Solar System. However, little is known about cometary nuclei since they are very difficult to observe due to the obscuring coma. READ MORE

  6. 14. The faintest stars : A study of white, red and brown dwarfs

    Author : Leif Festin; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy; brown dwarfs; white dwarfs; M dwarf; low luminosity; luminosity function; mass function; Pleiades; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; astronomi; Astronomy;

    Abstract : The local space density of the faintest stars, including M dwarfs, white dwarfs and brown dwarfs has been studied by two different methods.By using dark nebulae as opaque outer screens, the luminosity functions of M dwarfs and white dwarfs were studied as volume-limited and dynamically unbiassed foreground samples. READ MORE

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

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

    Abstract : 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. READ MORE