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E. K. S. Hicks, M. A. Malkan (UCLA)
Two-dimensional nuclear gas kinematics have been measured for a sample of seven Seyfert 1 galaxies. The inner arcsecond of each active galactic nucleus is well sampled at 0''.1 spatial resolution with Keck single slit NIRSPEC K-band spectroscopy obtained with adaptive optics. Velocity and flux distribution maps have been created for ionized hydrogen and several molecular hydrogen emission lines, as well as coronal lines, where available. Molecular and ionized hydrogen velocity fields show steep gradients of 100-150 km s-1 across the central tenths of an arcsecond in four galaxies. The two-dimensional gas kinematics are interpreted using dynamical models; these provide an estimate for the central mass in each Seyfert 1, presumably a supermassive black hole. The models assume a co-planar thin disk undergoing circular rotation, and take into account the point spread function for each spectroscopic exposure (measured simultaneously using the slit viewing camera) and the emission line surface brightness distribution. Also included in the models are the stellar gravitational fields, which are estimated from HST NICMOS near-infrared images by separating the stellar light from the point source and assuming a constant mass-to-light ratio. Compared to most non-active spiral galaxies, the Seyfert 1 galaxies appear to have higher stellar surface densities in the inner two arcseconds. Black hole mass estimates are consistent with or a bit higher than those given by the reverberation mapping technique.
The author(s) of this abstract have provided an email address for comments about the abstract: ehicks@astro.ucla.edu
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.