Search for dissertations about: "institutionen för astronomi."

Showing result 21 - 25 of 340 swedish dissertations containing the words institutionen för astronomi..

  2. 21. Microphysical Conditioning of Gamma-Ray Burst Shocks

    Author : Jacob Trier Frederiksen; Claes Fransson; Åke Nordlund; Mikhail V. Medvedev; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; magnetic fields; particle acceleration; plasma instabilities; gamma-ray bursts; collisionless shocks; relativistic outflows; Astronomy and astrophysics; Astronomi och astrofysik; Astronomy; astronomi;

    Abstract : Gamma-Ray Bursts (GRBs) are believed to be connected with either collapse of massive stars or – in some cases – coalescing neutron stars, both of which cause extreme relativistic explosions observable from the entire Universe. GRBs produce rapid flashes of high energy radiation, extending up to 2MeV in photon energies: as much energy per photon as the rest mass of 4 electrons. READ MORE

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

    Author : Erik Zackrisson; Nils Bergvall; Kjell Olofsson; Julianne Dalcanton; Uppsala universitet; []
    Keywords : 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;

    Abstract : 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. READ MORE

  5. 23. Exploring the nature of ISM turbulencein disc galaxies

    Author : Timmy Ejdetjärn; Göran Östlin; Oscar Agertz; Garrelt Mellema; Troels Haugbølle; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; galaxies; galaxy; disc galaxy; star formation; ISM; interstellar medium; kinematics; dynamics; evolution; turbulence; numerical; Astronomy; astronomi; teoretisk astrofysik; Theoretical Astrophysics;

    Abstract : Galaxy formation is a continuous process that started only a few hundred million yearsafter the Big Bang. The first galaxies were very volatile, with bursts of star formationand disorganised gas motions. READ MORE

  6. 24. Ionized and atomic interstellar medium in star-forming galaxies

    Author : Thøger Emil Rivera-Thorsen; Göran Östlin; Matthew Hayes; Dawn Erb; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy; astronomi;

    Abstract : Star forming galaxies in the local Universe are an important laboratory for learning about conditions in the distant, early Universe. With a high frequency of interactions and mergers, strong star formation activity, and complex kinematics and often disturbed or irregular morphology, these galaxies are believed to be the best local analogs to the galaxies at early times, and can therefore help understand the galaxies we observe at high redshifts in the early Universe. READ MORE

  7. 25. High-contrast imaging of faint substellar companions and debris disks

    Author : Rubén Asensio Torres; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy; astronomi;

    Abstract : Star formation results in the accumulation of circumstellar material orbiting around their host stars, such as debris disks and planetary-mass objects. A relatively modern technique that has shown to be very valu- able for studying these faint companions is high-contrast imaging, which allows to distinguish the light emitted or scattered off these objects, otherwise hidden behind the brighter stellar halo. READ MORE