Sökning: "Astronomy with specialization in Astrophysics"
Visar resultat 1 - 5 av 12 avhandlingar innehållade orden Astronomy with specialization in Astrophysics.
1. The Extremes of Neutrino Astronomy : From Fermi Bubbles with IceCube to Ice Studies with ARIANNA
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
2. Magnetic fields and chemical maps of Ap stars from four Stokes parameter observations
Sammanfattning : Our knowledge of stellar magnetic fields relies almost entirely on circular polarization observations, which has historically limited our understanding of the stellar magnetic field topologies. Recently, it has become possible to obtain phase-resolved high-resolution spectropolarimetric observations in all four Stokes parameters for early-type magnetic stars. LÄS MER
3. Atomic Processes in Stellar Atmospheres : Inelastic Collisions and Effects on Late-type Spectra
Sammanfattning : Chemical abundances as measured from stellar spectral lines are often subject to uncertainties due to lack of accurate data for inelastic collisions, which is needed for non-local thermodynamic equilibrium (non-LTE) modelling. For cool stars, understanding of collision processes with electrons and hydrogen atoms is required to achieve high precision measurements. LÄS MER
4. Magnetic Fields and Chemical Spots in HgMn Stars
Sammanfattning : Mercury-manganese (HgMn) stars belong to the class of chemically peculiar (CP) stars. It was recently discovered that some HgMn stars have spots of chemical elements on their surfaces. LÄS MER
5. Bright Needles in a Haystack : A Search for Magnetic Monopoles Using the IceCube Neutrino Observatory
Sammanfattning : The IceCube Neutrino Observatory at the geographic South Pole is designed to detect the light produced by the daughter-particles of in-ice neutrino-nucleon interactions, using one cubic kilometer of ice instrumented with more than 5000 optical sensors.Magnetic monopoles are hypothetical particles with non-zero magnetic charge, predicted to exist in many extensions of the Standard Model of particle physics. LÄS MER