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B. McKernan (Coastal Carolina U.), C. S. Reynolds (U. Md College Park), T. Yaqoob (Johns Hopkins U., NASA GSFC)
Two-thirds of type I AGN exhibit outflows of ionized absorbing gas. The location, origin and dynamics of these ionized outflows are poorly understood. I will present the results from the first uniform analysis of the ionized absorbers in a small sample of type I AGN observed with the gratings on board the Chandra X-ray telescope.
Our results for the hot outflows from AGN agree well with the model of Krolik & Kriss of photoionized evaporation of a dusty torus. The mass carried by the hot outflows seems very high; it is comparable with the expected accretion rate onto the black hole, as predicted by Krolik & Kriss. The measured distance of the hot gas from the continuum source is also consistent with the Krolik & Kriss model, if the electron density in the hot gas is \leq 108 \rm{cm}-3. The Elvis model of hot outflows from AGN, namely a vertical disk wind, blown outwards in a funnel-shaped outflow, is much more strongly constrained by our work. The parameter space of the hot outflows is relatively small, suggesting both a narrow angle of AGN inclination and a narrow range of parameters for the disk wind. The Elvis model predicts that the Fe K line is produced in the hot outflow and not in the accretion disk. However, we find that there is no correlation between the equivalent width of the Fe K line and the column density of gas in the hot outflow.
One new result was only obtainable from a uniform analysis of a sample of AGN. We find, intriguingly, that the larger the rate of growth of the AGN central black hole, apparently the \emph{smaller} the velocity of the hot outflow.
We gratefully acknowledge support from NSF grant AST0205990 & from Coastal Carolina University.
The author(s) of this abstract have provided an email address for comments about the abstract: mckernan@coastal.edu
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.