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Title: Variability and black hole mass in active galactic nuclei
Author: Skelton, Jessica
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2005
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Optical observations of a sample of narrow-line and classical broad-line Seyfert 1 galaxies are presented. Off-nuclear spectra of the bulge were used to obtain the line-of-sight stellar velocity dispersion σ*. Nuclear spectra were used to remove residual nuclear emission from the bulge spectra and to calculate single-epoch virial black hole mass estimates. The two samples were augmented using objects taken from the literature. The optical flux variability of the least-luminous known Seyfert 1 galaxy, NGC 4395, has been a matter of controversy, with a number of apparently contradictory reports. An observed short time-scale continuum variability is consistent with NGC 4395 having an intermediate-mass (~ 105M) central supermassive black hole, rather than a very low accretion rate. Comparison with the Seyfert 1 galaxy NGC 5548 shows that the observed variability seems to scale with black hole mass in roughly the manner expected in accretion models. However the absolute timescale of variability differs by several orders of magnitude from that expected in simple accretion disc models in both cases.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available