Sökning: "gamma-ray burst"

Visar resultat 1 - 5 av 10 avhandlingar innehållade orden gamma-ray burst.

  1. 1. Photospheric emission in gamma ray bursts : Analysis and interpretation of observations made by the Fermi gamma ray space telescope

    Författare :Shabnam Iyyani; Felix Ryde; David Burrows; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; gamma ray bursts; photosphere; radiation mechanism; Theoretical Physics; teoretisk fysik;

    Sammanfattning : The large flashes of radiation that are observed in GRBs are generally believed to arise in a relativistic jetted outflow. This thesis addresses the question of how and where in the jet this radiation is produced. LÄS MER

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

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

    Sammanfattning : 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. LÄS MER

  4. 3. Photospheric emission from structured, relativistic jets : applications to gamma-ray burst spectra and polarization

    Författare :Christoffer Lundman; Felix Ryde; Andrei Beloborodov; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; gamma-ray bursts; photospheric emission; radiative processes; polarization; special relativity;

    Sammanfattning : The radiative mechanism responsible for the prompt gamma-ray burst (GRB) emission remains elusive. For the last decade, optically thin synchrotron emission from shocks internal to the GRB jet appeared to be the most plausible explanation. LÄS MER

  5. 4. Interpretation of gamma-ray burst X-ray and optical afterglow emission : From the central engine to the circumburst interaction

    Författare :Liang Li; Felix Ryde; Fawad Hassan; Kim Page; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; gamma-ray bursts; central engine; afterglow; teoretisk fysik; Theoretical Physics;

    Sammanfattning : Gamma-ray bursts are the largest electromagnetic explosions known to happen in the Universe and are associated with the collapse of stellar progenitors into blackholes. After an energetic prompt emission phase, lasting typically less than a minute and emitted in the gamma-rays, a long-lived afterglow phase starts. LÄS MER

  7. 5. Search for Neutrinos from Gamma-ray Bursts using the IceCube Neutrino Observatory

    Författare :Kunal Avinash Deoskar; Chad Finley; Klas Hultqvist; Paschal Coyle; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Gamma-ray bursts; neutrinos; IceCube Neutrino Observatory; Physics; fysik;

    Sammanfattning : Gamma ray bursts (GRBs) are short bursts of high energy γ-radiation and are among some of the most energetic phenomena in the universe. GRBs have three distinct emission phases: the prompt phase with high-energy γ-rays, the precursor phase which is the time interval before the prompt phase and is reported to have an additional smaller burst for some GRBs, and the afterglow phase which is the time interval after the prompt phase with observations for electromagnetic radiation across a large wavelength range reported for many GRBs. LÄS MER