Search for dissertations about: "VLBI"

Showing result 21 - 25 of 27 swedish dissertations containing the word VLBI.

  2. 21. Methanol Masers: Tracer of Star Formation

    Author : Vincent Minier; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Abstract : The Onsala VLBI group has been conducting an extensive study of the Northern hemisphere methanol masers using the European VLBI Network (EVN) and the VLBA since early 1997. In parallel, a blind survey of the Galactic plane has been undertaken in order to discover new 6. READ MORE

  4. 22. Investigating the origin of radio emission in nearby starburst galaxies via high-resolution metre and centimetre observations

    Author : Eskil Varenius; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; galaxies: individual: M 82; galaxies: starburst; galaxies: individual: Arp 220; stars: supernovae; galaxies: individual: NGC 4418; radio continuum: galaxies; techniques: high angular resolution;

    Abstract : Star formation and galaxy evolution are intimately linked together. A detailed understanding of the physics of star formation can help us explain how galaxies evolve into, for example, our present Milky Way. READ MORE

  5. 23. Time and Frequency Transfer using Passive Techniques in Active Fiber Optic Networks

    Author : Sven-Christian Ebenhag; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fiber link; optical fiber.; Global positioning system GPS ; fiber network; time transfer; two-way; synchronous optical networking SONET synchronous digital hierarchy SDH ; GPS carrier phase;

    Abstract : For the modern society, high precision time and frequency transfer have become crucial since a large number of systems, such as telecommunication systems, require precise and stable synchronization. Electric power companies use synchronized systems for taking stability measurements and searching for errors in their networks. READ MORE

  6. 24. Radio Studies of Circumnuclear Gas in Active Galaxies

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

    Abstract : 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. READ MORE

  7. 25. High Resolution Studies of Circumstellar Masers

    Author : Francisco Colomer Sanmartin; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Abstract : This thesis describes in detail the observational procedures that we have followed and developed to analyze several research projects organized at Onsala since 1990 to study the regions of SiO maser emission at 43 GHz in the circumstellar envelopes of late-type stars with very high angular resolution. The compact nature of these SiO maser regions has been demonstrated in this work. READ MORE