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Paper: Black Hole Mass Estimates in Narrow-Line Seyfert 1 Galaxies
Volume: 381, The Second Annual Spitzer Science Center Conference: Infrared Diagnostics of Galaxy Evolution
Page: 446
Authors: Ryan, C.J.; De Robertis, M.M.; Virani, S.; Laor, A.; Dawson, P.C.
Abstract: It has been suggested that Narrow-Line Seyfert 1 (NLS1) galaxies are evolutionarily young objects, powered by accretion onto black holes that are lower in mass than those found in typical broad-line Seyferts. We explore this hypothesis through the analysis of high-spatial resolution, near-IR imaging data for a sample of 11 NLS1s. Surface brightness profiles are separated into their constituent components using two-dimensional decomposition techniques. By employing the correlation between black hole mass and host galaxy bulge luminosity, we determine the mean black hole mass for our sample to be, in solar units, 〈log(MBH)〉 = 7.9. Virial mass estimates are obtained for seven of the objects in our sample using the correlation between the size of the broadline region and the monochromatic continuum luminosity, as calibrated from reverberation mapping studies. The mean black hole mass derived from this relation is 〈log(MBH)〉 = 6.4. We thus find that the estimates obtained from the mass-luminosity relation are more than one order of magnitude larger than those based on reverberation mapping. Furthermore, because numerical simulations constrain the start of the AGN duty cycle to a time shortly after a significant gravitational interaction, we examine the morphology and near-IR bulge colors of the NLS1 sample. No evidence is found for asymmetries or a stellar content that would indicate NLS1s are young objects. Finally, we postulate that there may be some interesting lines of circumstantial evidence suggesting that secular processes may be relevant in NLS1s.
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