Sökning: "Galaxy"

Visar resultat 11 - 15 av 150 avhandlingar innehållade ordet Galaxy.

1. 11. 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

3. 12. 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

4. 13. Photometry of Resolved Stellar Populations in Local Group Galaxies

   Författare :Daniel Faria; Astronomi - Genomgår omorganisation; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomi; Astronomy; Local Group; Galaxy: halo; Galaxies: dwarf; Galaxy: stellar content; Galaxies: photometry; Techniques: photometric; Stars: fundamental parameters;

   Sammanfattning : This thesis presents results from two projects using photometric observations to investigate stellar populations in Local Group galaxies. In the first project, Strömgren photometry is used to study stellar populations in dwarf spheroidal galaxies. LÄS MER

5. 14. Molecular gas in the galaxy M83 : Its distribution, kinematics, and relation to star formation

   Författare :Andreas Andersson Lundgren; Hans Olofsson; John Whiteoak; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Molecular gas; Galaxies; Galaxies individual: M83; Star formation; Galactic dynamics; Astronomy and astrophysics; Astronomi och astrofysik;

   Sammanfattning : The barred spiral galaxy M83 (NGC5236) has been observed in the 12CO J=1–0 and J=2–1 millimetre lines with the Swedish-ESO Submillimetre Telescope (SEST). The sizes of the CO maps are 100×100, and they cover the entire optical disk. The CO emission is strongly peaked toward the nucleus. LÄS MER

7. 15. Active Galactic Nuclei in galaxy surveys : Empirical paths to the fiery hearts of cosmic beasts

   Författare :Beatriz Villarroel; Andreas J. Korn; Takis Konstantopoulos; Moshe Elitzur; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; Astronomi;

   Sammanfattning : Some galaxies emit excessive amounts of light from their centers, caused by accretion of gas onto super-massive black holes (SMBH). These galactic cores are often referred to as Active Galactic Nuclei (AGN) and they come in many different forms, distinguishable by their emission properties. LÄS MER