Search for dissertations about: "Astronomy with specialization in Astrophysics"

Showing result 1 - 5 of 12 swedish dissertations containing the words Astronomy with specialization in Astrophysics.

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

    Author : Elisabeth Unger; Allan Hallgren; Olga Botner; Antonio Capone; Uppsala universitet; []
    Keywords : 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;

    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

  4. 2. Magnetic fields and chemical maps of Ap stars from four Stokes parameter observations

    Author : Naum Rusomarov; Oleg Kochukhov; Nikolai Piskunov; Werner Weiss; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; chemically peculiar stars; magnetic fields; spectropolarimetry; Doppler imaging; stellar atmospheres; Astronomy with specialization in Astrophysics; Astronomi med intiktning mot astrofysik; Astronomy; Astronomi;

    Abstract : 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. READ MORE

  5. 3. Atomic Processes in Stellar Atmospheres : Inelastic Collisions and Effects on Late-type Spectra

    Author : Yeisson Fabian Martinez Osorio; Paul Barklem; Karin Lind; Nikolai Piskunov; Carlos Allende Prieto; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Spectral line: formation; atomic data; stellar abundances.; Fysik med inriktning mot astrofysik; Physics with specialization in Astrophysics;

    Abstract : 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. READ MORE

  6. 4. Magnetic Fields and Chemical Spots in HgMn Stars

    Author : Vitalii Makaganiuk; Oleg Kochukhov; Nikolai Piskunov; Gregg Wade; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Chemically peculiar stars; magnetic fields; spectropolarimetry; Doppler imaging; Astronomy with specialization in Astrophysics; Astronomi med intiktning mot astrofysik;

    Abstract : 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. READ MORE

  7. 5. Bright Needles in a Haystack : A Search for Magnetic Monopoles Using the IceCube Neutrino Observatory

    Author : Alexander Burgman; Carlos Pérez de los Heros; Olga Botner; Allan Hallgren; David Milstead; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; magnetic monopole; IceCube; astroparticle physics; neutrino telescope; Fysik med inriktning mot elementarpartikelfysik; Physics with specialization in Elementary Particle Physics;

    Abstract : 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. READ MORE