Search for dissertations about: "High energy astrophysics"
Showing result 11 - 15 of 64 swedish dissertations containing the words High energy astrophysics.
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11. Measurements of High-Precision Atomic Data with Applications to Astrophysics and Cosmology
Abstract : Investigations of astrophysical spectra require accurate atomic data, such as wavelengths and transition probabilities. This thesis provides high-precision atomic data for astrophysical and cosmological applications. The measurements have been carried out using Fourier transform spectrometry on light produced in a hollow cathode light source. READ MORE
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12. The environment of high-redshift AGN
Abstract : In order to understand the formation and evolution of local massive galaxies and to reveal the processes that engineered the tight correlations found between their supermassive black hole (SMBH) mass and bulge mass or velocity dispersion, the study of powerful, high-redshift active galactic nuclei (AGN) and their environment is crucial. Observations of high-z quasars and radio galaxies suggest that these AGN live in overdense environment surrounding by star-forming Ly&alpha-emitters and submillimeter galaxies. READ MORE
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13. Searching for dark matter in the Galactic Halo with IceCube using high energy cascades
Abstract : The presence of dark matter is inferred at scales ranging from rotations of galaxies to imprints in the CMB – the Big Bang after-glow. The nature of dark matter is, however, still unknown as no detection other than the gravitational one has been made. READ MORE
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14. 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
Abstract : 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. READ MORE
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15. The Extremes of Neutrino Astronomy : From Fermi Bubbles with IceCube to Ice Studies with ARIANNA
Abstract : 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. READ MORE