High frequency VLBI studies of Sagittarius A_1hn* and NRAO 530 [Elektronische Ressource] / vorgelegt von Ru-Sen Lu
156 Pages
English

High frequency VLBI studies of Sagittarius A_1hn* and NRAO 530 [Elektronische Ressource] / vorgelegt von Ru-Sen Lu

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High Frequency VLBI Studies of Sagittarius A*and NRAO 530Inaugural-DissertationzurErlangung des Doktorgradesder Mathematisch-Naturwissenschaftlichen Fakulta¨t¨ ¨der Universitat zu Kolnvorgelegt vonRu-Sen Luaus Hebei, ChinaKo¨ln 2010Berichterstatter:1.Gutachter: Prof. Dr. J. Anton Zensus2.Gutachter: Prof. Dr. Andreas EckartTag der mu¨ndlichen Pru¨fung: 13.07.2010To my parents and the rest of my famillyiAbstractCompact radio sources (Kellermann & Pauliny-Toth 1981) are widely accepted to beassociated with supermassive black holes at the centers of active galaxies. Very longbaseline interferometry (VLBI) observations at short millimeter wavelengths offer theunique advantage to look “deeper” into the central core regions. In this thesis we studytwo compact radio sources (Sagittarius A* and NRAO 530) with high frequency VLBItechniques.As a starting point, we give in Chapter 1 a general introduction to observationalproperties of Active galactic nuclei (AGNs) and a theoretical basis. In Chapter 2, thecompact radio source at the center of the Milky Way, Sagittarius A*, is reviewed. InChapter 3, the technical basis of VLBI is outlined and then the difficulties of VLBI(and therefore the ways to improve) at short millimeter wavelengths are discussed.Due to its proximity, Sagittarius A* has the largest apparent event horizon of anyblack hole candidate and therefore it provides a unique opportunity for testing theSMBH paradigm.

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Published 01 January 2010
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Language English
Document size 7 MB