Sökning: "GeV gamma-rays"

Visar resultat 1 - 5 av 8 avhandlingar innehållade orden GeV 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. 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

4. 3. Search for Gamma-ray Lines from Dark Matter with the Fermi Large Area Telescope

   Författare :Tomi Ylinen; Mark Pearce; Jan Conrad; Staffan Carius; James T. Linnemann; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Fermi; Large Area Telescope; gamma-rays; dark matter; spectral lines; beam test; Physics; Fysik; Astroparticle physics; Astropartikelfysik;

   Sammanfattning : Dark matter (DM) constitutes one of the most intriguing but so far unresolved issues in physics. In many extensions of the Standard Model of particle physics, the existence of a stable Weakly Interacting Massive Particle (WIMP) is predicted. The WIMP is an excellent DM particle candidate. LÄS MER

5. 4. The Extremes of Neutrino Astronomy : From Fermi Bubbles with IceCube to Ice Studies with ARIANNA

   Författare :Elisabeth Unger; Allan Hallgren; Olga Botner; Antonio Capone; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; astroparticle physics; neutrino telescopes; IceCube; Fermi bubbles; ARIANNA; horizontal propagation; surface wave propagation; Fysik med inriktning mot elementarpartikelfysik; Physics with specialization in Elementary Particle Physics; High Energy Physics; Högenergifysik;

   Sammanfattning : The Fermi bubbles are extended regions of hard gamma-ray emission which were discovered with Fermi-LAT data to exist above and below the Galactic Center. In order to explain the origin of the gamma-rays, different theories are proposed. LÄS MER

7. 5. A Search for Dark Matter Lines with H.E.S.S. II

   Författare :Knut Dundas Morå; Jan Conrad; Christian Farnier; Christian Walck; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Dark Matter; Cherenkov Telescopes; Indirect Detection; fysik; Physics;

   Sammanfattning : Most of the matter in the universe, ~80% is thought to be dark matter- particles that have small or no interactions with standard model particles. Dark matter is an integral part of the current understanding of cosmology, and leaves signs in the movements of stars and galaxies, as well as the Cosmic Microwave Background. LÄS MER