Sökning: "photospheric emission"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden photospheric emission.

  1. 1. 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

  3. 2. Photospheric emission in gamma-ray bursts

    Författare :Christoffer Lundman; Felix Ryde; Stephan Rosswog; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : This thesis considers emission from gamma-ray bursts (GRBs), the most powerful explosions known in the Universe. Most GRBs are likely associated with the final stages of stellar evolution, where the core of a massive star collapses, and gives birth to a highly compact object such as a neutron star or black hole. LÄS MER

  4. 3. 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

  5. 4. Circumstellar dust emission from nearby Solar-type stars

    Författare :Joachim Wiegert; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Stars: binaries - Stars: circumstellar matter - Infrared: stars - Infrared: planetary systems - Submillimeter: stars;

    Sammanfattning : Far-infrared excess above the photosphere of a star indicates the presence of a circumstellar dust disc which is a sign-post for extrasolar planets, and was first detected in the mid 1980s. Dust discs are intricately connected to planets and planetesimals, give insights in the dynamics and evolution of the system, and are also useful for future exoplanet-observations. LÄS MER

  7. 5. Non-Local Thermodynamic Equilibrium Spectral Modelling of Kilonovae

    Författare :Quentin Pognan; Anders Jerkstrand; Kyohei Kawaguchi; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Transients: Neutron Star Mergers; Radiative Transfer; Astronomy; astronomi;

    Sammanfattning : The astrophysical origin of rapid neutron capture (r-process) elements has long remained a puzzle and been the object of scientific debate. Neutron star (NS) mergers have historically been suggested as an ideal site for the creation of these elements, and were propelled into focus following the detection of the first binary neutron star (BNS) merger in 2017. LÄS MER