Sökning: "gamma-rays"

Visar resultat 1 - 5 av 56 avhandlingar innehållade ordet gamma-rays.

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. Seeking the faint extremes : Detection and characterisation of extragalactic soft-spectrum gamma-ray sources and exploring methods to enhance their detection with machine learning in the 50 GeV-50 TeV energy range

   Författare :Tomas Bylund; Yvonne Becherini; Gilles Henri; Linnéuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; GeV gamma-rays; TeV gamma-rays; AGN; blazar; deep learning; observational high-energy astronomy; Astroparticle Physics; Astropartikelfysik;

   Sammanfattning : This thesis deals with an observational study of Blazars, strong gamma-ray sources with Very High Energies (VHE) located far outside our Galaxy. Blazars are a class of galaxies that contain a supermassive black hole that is actively consuming large quantities of matter, a process that results in the liberation of tremendous amounts of energy that then powers the emission of huge bulks of charged particles that get accelerated almost to the speed of light. LÄS MER

5. 4. Experimental studies of gamma rays from neutron reactions

   Författare :Börje Lundberg; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : .... LÄS MER

7. 5. Parametric Model for Astrophysical Proton-Proton Interactions and Applications

   Författare :Niklas Karlsson; Per Carlson; Simon Swordy; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; astrophysics; gamma rays; proton-proton interactions; cosmic rays; Astronomy and astrophysics; Astronomi och astrofysik;

   Sammanfattning : 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. LÄS MER