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Visar resultat 1 - 5 av 22 avhandlingar som matchar ovanstående sökkriterier.

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

    Författare :Stephan Zimmer; Jan Conrad; Christophe Clement; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; galaxy clusters; gamma rays; cosmic rays; dark matter; fermi-lat; likelihood analysis; joint likelihood;

    Sammanfattning : 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. LÄS MER

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

    Författare :Stephan Zimmer; Jan Conrad; Lars Bergström; Torsten Enßlin; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Galaxy Clusters; Fermi-LAT; γ rays; Dark Matter; Cosmic Rays; fysik; Physics;

    Sammanfattning : 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. LÄS MER

  4. 3. Cosmic rays and shock physics in gamma-ray bursts

    Författare :Filip Samuelsson; Felix Ryde; Robert Mochkovitch; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; astrophysics; gamma-ray bursts; cosmic rays; radiation-mediated shocks; Atomic; Subatomic and Astrophysics; Atomär fysik; subatomär fysik och astrofysik;

    Sammanfattning : Gamma-ray bursts (GRBs) are the most luminous events in the known universe. Due to their tremendous energy output, they serve as laboratories of physics far beyond anything that we can hope to achieve in terrestrial experiments. LÄS MER

  5. 4. Search for rare neutral two-body channels in the pp annihilation at rest : performed by measurments of high energy γ-rays using a modular NaI(Tl)-spectrometer

    Författare :Lars Adiels; Ingmar Bergström; Erik Johansson; Kungliga Tekniska högskolan; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Fysik; fysik; Physics;

    Sammanfattning : .... LÄS MER

  7. 5. Nuclear Structure Studies near 208Pb and γ-ray Imaging Techniques

    Författare :Natasa Lalovic; Kärnfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; nuclear structure; gamma-Ray spectroscopy; AGATA; isomeric decays; relativistic projectile fragmentation; Pb isotopes; nuclear structure; gamma-ray spectroscopy; AGATA; isomeric decays; relativistic projectile fragmentation; Pb isotopes;

    Sammanfattning : This thesis focuses on a high-resolution γ-ray spectroscopy experiment where the fragmenta- tion of a 208 Pb primary beam was used to populate even-mass nuclei around 208 Pb. It was conducted in 2012 using the Advanced GAmma-ray Tracking Array (AGATA) while it was placed at GSI Darmstadt, Germany. LÄS MER