Sökning: "Galaxies: nuclei"

Visar resultat 1 - 5 av 24 avhandlingar innehållade orden Galaxies: nuclei.

  1. 1. Molecular observations of obscured galaxy nuclei

    Författare :Niklas Falstad; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Galaxies: nuclei; Galaxies: ISM; Infrared: galaxies; ISM: Molecules; Submillimeter: galaxies;

    Sammanfattning : It is becoming evident that some (ultra)luminous infrared galaxies ((U)LIRGs) contain compact obscured nuclei (CONs) where luminosities in excess of 10^9 L☉  emerge from inside dusty regions smaller than 100 pc in diameter. Due to the obscured nature of these objects, their inner regions are hidden from examination using optical or infrared lines. LÄS MER

  3. 2. Radio Studies of Circumnuclear Gas in Active Galaxies

    Författare :Ylva Pihlström; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; techniques: interferometry; galaxies: starbust; galaxies: active; galaxies: nuclei; radio lines: galaxies; techniques: high angular resolution;

    Sammanfattning : In this thesis we have used radio interferometry in order to perform high resolution spectral line studies of circumnuclear gas in AGN and starburst galaxies. Amongst the studied objects is the Seyfert 2 NGC5793, for which we find the high opacity HI absorption to be consistent with a 50-100 pc radius atomic disk aligned with the host galaxy disk. LÄS MER

  4. 3. Molecular Gas in Seyfert Galaxies

    Författare :S.J. Curran; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; star-burst-nuclei-dynamics; galaxies; star-burst-nuclei-kinematics; interstellar medium molecules; Seyfert;

    Sammanfattning : In this report we present the results of a single dish study of the molecular gas properties in Seyfert galaxies. From the observations of the closest lying example, the Circinus galaxy, we find that about half of the molecular gas is distributed in a circumnuclear ring orbiting the central super-massive black hole, believed to be powering this type 2 Seyfert. LÄS MER

  5. 4. Water and hydroxyl in luminous infrared galaxies: Spectroscopic observations and modelling

    Författare :Niklas Falstad; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ISM: molecules; Galaxies: individual: Zw 049.057; Line: formation; Galaxies: ISM; Submillimeter: galaxies; Infrared: galaxies;

    Sammanfattning : Many luminous infrared galaxies (LIRGs) contain compact obscured nuclei (CONs) where luminosities in excess of 10^9 Lsun emerge from inside dusty regions smaller than 100 pc in diameter. Due to the obscuring material in these regions, the nature of the nuclear power source cannot be determined using direct observations in the optical or IR. LÄS MER

  7. 5. On the Escape of Lyman Radiation from Local Galaxies

    Författare :Elisabet Leitet; Nils Bergvall; Erik Zackrisson; Bengt Gustafsson; Duilia F. De Mello; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Galaxies; starbursts; spiral galaxies; Lyman continuum; Lyman alpha; leakage; cosmic reionization; escape fraction; Astronomy; Astronomi;

    Sammanfattning : Cosmic reionization was most likely initiated by star forming dwarf galaxies. Little is known about the physical mechanisms allowing ionizing Lyman continuum (LyC) photons to escape from galaxies, but to learn more we can study local galaxies in detail. LÄS MER