Search for dissertations about: "gamma rays"

Showing result 1 - 5 of 61 swedish dissertations containing the words gamma rays.

  1. 1. Gamma-Ray Emission from Galaxy Clusters DARK MATTER AND COSMIC-RAYS

    University dissertation from Stockholm : Department of Physics, Stockholm University

    Author : Anders Pinzke; Stockholms universitet.; [2010]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Galaxy clusters; gamma-rays; cosmic-rays; dark matter; NATURAL SCIENCES Physics Astronomy and astrophysics High energy astrophysics; NATURVETENSKAP Fysik Astronomi och astrofysik Högenergiastrofysik; teoretisk fysik; Theoretical Physics;

    Abstract : The quest for the first detection of a galaxy cluster in the high energy gamma-ray regime is ongoing, and even though clusters are observed in several other wave-bands, there is still no firm detection in gamma-rays.To complement the observational efforts we estimate the gamma-ray contributions from both annihilating dark matter and cosmic-ray (CR) proton as well as CR electron induced emission. READ MORE

  2. 2. Searching for Gamma Rays from Galaxy Clusters with the Fermi Large Area Telescope Cosmic Rays and Dark Matter

    University dissertation from Stockholm : Stockholm University

    Author : Stephan Zimmer; Stockholms universitet.; Stockholms universitet.; [2013]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; galaxy clusters; gamma rays; cosmic rays; dark matter; fermi-lat; likelihood analysis; joint likelihood;

    Abstract : In this licentiate thesis, I report a search for GeV γ rays towards the location of Galaxy clusters. I mainly discuss the results of a search for cosmic-ray (CR) induced γ-ray emission but also briefly elaborate on a related study, searching for Dark Matter (DM)-induced γ-ray emission from Galaxy clusters. READ MORE

  3. 3. Observations of nearby Galaxy Clusters with the Fermi Large Area Telescope Towards the first Gamma Rays from Clusters

    University dissertation from Stockholm : Department of Physics, Stockholm University

    Author : Stephan Zimmer; Stockholms universitet.; [2015]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Galaxy Clusters; Fermi-LAT; γ rays; Dark Matter; Cosmic Rays; Physics; fysik;

    Abstract : Galaxy clusters are the most massive bound systems known in the Universe and are believed to have formed through large scale structure formation. They host relativistic cosmic-ray (CR) populations and are gravitationally bound by large amounts of Dark Matter (DM), both providing conditions in which high-energy gamma rays may be produced either via CR interactions with the intracluster medium or through the annihilation or decay of DM particles. READ MORE

  4. 4. Parametric Model for Astrophysical Proton-Proton Interactions and Applications

    University dissertation from Stockholm : KTH

    Author : Niklas Karlsson; KTH.; [2007]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; astrophysics; gamma rays; proton-proton interactions; cosmic rays; NATURAL SCIENCES Physics Astronomy and astrophysics; NATURVETENSKAP Fysik Astronomi och astrofysik;

    Abstract : Observations of gamma-rays have been made from celestial sources such as active galaxies, gamma-ray bursts and supernova remnants as well as the Galactic ridge. The study of gamma rays can provide information about production mechanisms and cosmic-ray acceleration. READ MORE

  5. 5. Study of Two-Photon processes at low Q2 using the VSAT calorimeter in the DELPHI experiment

    University dissertation from Lund University

    Author : Pavel Tyapkin; Lund University.; Lunds universitet.; [2004]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; högenergi; QCD; STIC; VSAT; DELPHI; LEP; antitag; double tag; single tag; photon structure function; hadronic cross-section; virtual photons; two-photon; gamma-gamma; Kosmisk strålning; cosmic rays; High energy interactions; PHOJET; TWOGAM; PYTHIA; VDM; GSP; Fysicumarkivet A:2004:Tyapkin;

    Abstract : The study is based on data collected at the LEP II accelerator during the second period of the Large Electron-Positron collider operations (1996-2000). During that time the DELPHI (DEtector with Lepton, Photon and Hadron Identification) experiment collected about 90 Gb of data on tape corresponding to 687-691 pb-1 of luminosity. READ MORE