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dc.contributor.advisorWeaver, Kimberlyen_US
dc.contributor.advisorReynolds, Christopheren_US
dc.contributor.authorMattson, Barbaraen_US
dc.date.accessioned2008-06-20T05:35:36Z
dc.date.available2008-06-20T05:35:36Z
dc.date.issued2008-04-24en_US
dc.identifier.urihttp://hdl.handle.net/1903/8133
dc.description.abstractWith over forty years of X-ray observations, we should have a grasp on the X-ray nature of active galactic nuclei (AGN). The unification model of Antonucci and Miller (1985) offered a context for understanding observations by defining a "typical" AGN geometry, with observed spectral differences explained by line-of-sight effects. However, the emerging picture is that the central AGN is more complex than unification alone can describe. We explore the unified model with a systematic X-ray spectral study of bright Seyfert galaxies observed by the Rossi X-Ray Timing Explorer (RXTE) over its first 10 years. We develop a spectral-fit database of 821 time-resolved spectra from 39 Seyfert galaxies fitted to a model describing the effects of an X-ray power-law spectrum reprocessed and absorbed by material in the central AGN region. We observe a relationship between radio and X-ray properties for Seyfert 1s, with the spectral parameters differing between radio-loud and radio-quiet Seyfert 1s. We also find a complex relationship between the Fe K equivalent width (EW) and the power-law photon index (Gamma) for the Seyfert 1s, with a correlation for the radio-loud sources and an anti-correlation for the radio-quiet sources. These results can be explained if X-rays from the relativistic jet in radio-loud sources contribute significantly to the observed spectrum. We observe scatter in the EW-Gamma relationship for the Seyfert 2s, suggesting complex environments that unification alone cannot explain. We see a strong correlation between Gamma and the reflection fraction (R) in the Seyfert 1 and 2 samples, but modeling degeneracies are present, so this relationship cannot be trusted as instructive of the AGN physics. For the Seyfert 1 sample, we find an anticorrelation between EW and the 2 to 10 keV luminosity (L<sub>X</sub>), also known as the X-ray Baldwin effect. This may suggest that higher luminosity sources contain less material or may be due to a time-lag effect. We do not observe the previously reported relationship between Gamma and the ratio of L<sub>X</sub> to the Eddington luminosity.en_US
dc.format.extent8432652 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.titleA Decade of Rossi X-ray Timing Explorer Seyfert Observations:An RXTE Seyfert Spectral Databaseen_US
dc.typeDissertationen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.contributor.departmentAstronomyen_US
dc.subject.pqcontrolledPhysics, Astronomy and Astrophysicsen_US
dc.subject.pquncontrolledAGNen_US
dc.subject.pquncontrolledSeyfertsen_US
dc.subject.pquncontrolledRXTEen_US


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