Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 9 of 9 for “"Seyfert galaxies"”.
-
The relationship between the x-ray and optical variability in Seyfert Galaxies
… between the X-ray and optical variability in Seyfert galaxies by Elmé Breedt Lategan Seyfert galaxies have been known to vary since shortly after their discovery, but the origin of the optical variability and its relationship to the X-rays, have not been well established. Presented here is a …
-
X-Ray studies of the physics of matter around super-massive black-holes in nearby Seyfert galaxies
Seyfert galaxies are the closest active galactic nuclei. As such, we can use them to test the physical properties of the entire class of objects. To investigate their general properties, I took advantage of different methods of data analysis. In particular I used three different samples of objects, …
-
Models of Dust and Gas Tori in Active Galactic Nuclei
… to resolve dust structures in the centres of Seyfert galaxies. In a first step, we investigate an analytical torus model (the so-called "Turbulent Torus Model") with the help of radiative transfer calculations and find gross agreement with large aperture, as well as high-resolution …
-
The measurement and analysis of flux variations in Seyfert galaxy nuclei
Seyfert galaxies have compact nuclei with luminosities only surpassed by quasars, to which they are believed to be related. The most common interpretation of these objects is that their central power source is a black hole with matter accreting towards it. An understanding of these powerful energy …
-
Large-scale structure of the early universe
… 120 x 90 x 20h3 Mpc 3 , and a grouping of seven Seyfert galaxies at z 0.19, with dimensions of 60 X 30 X lOh' 3 Mpc3; • the members of quasar groups show no peculiar characteristics compared with a general population of quasars; • assuming that quasar groups are equivalent to present-day …
-
Towards a complete census of active galactic nuclei in the nearby Universe
As it is well established that almost all galaxies host a central supermassive black hole (SMBH), it is natural to ask, how many of these SMBHs are actively accreting? Studies aimed at answering this question can better define the fraction of nearby galaxies that harbour active galactic nuclei …
-
The complex interplay between AGN jet feedback and galaxy evolution
… holes (SMBHs), residing in the nuclei of most galaxies, are capable of imparting extreme amounts of energy to their surroundings. Observations indicate the presence of collimated, relativistic jets as well as powerful, multiphase winds emanating from these active galactic nuclei (AGN). Whilst …
-
On the Distances and Energetics of AGN Outflows
… of super-massive black holes and their host galaxies. As important as these outflows are, we still lack sufficient understanding of their structure and energetics. The majority of the work presented in this thesis involved photoionization modeling of AGN outflows along with analysis of …
-
A high energy perspective of the co-evolution of black holes and their host galaxies
… 2 quasars, and the X-ray bright optically normal galaxies, also known as XBONGs. In order to characterize the properties of these classes of elusive AGN, the datasets of several deep and large-area surveys have been fully exploited. The first class of “elusive” sources is characterized by …