Warm Absorbers and Outflows in the Seyfert-1 Galaxy NGC 4051

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We present both phenomenological and more physical photoionization models of the Chandra HETG spectra of the Seyfert-1 AGN NGC 4051. We detect 40 absorption and emission lines, encompassing highly ionized charge states from O, Ne, Mg, Si, S and the Fe L-shell and K-shell. Two independent photoionization packages, XSTAR and Cloudy, were both used to self-consistently model the continuum and line spectra. These fits detected three absorbing regions in this system with densities ranging from 10¹⁰ to 10¹¹ cm⁻³. In particular, our XSTAR models require three components that have ionization parameters of log ξ= 4.5, 3.3, & 1.0, and are located within the BLR at 70, 300, and 13,000 Rg, respectively, assuming a constant wind density. Larger radii are inferred for density profiles which decline with radius. The Cloudy models give a similar set of parameters with ionization parameters of log ξ= 5.0, 3.6, & 2.2 located at 40, 200, and 3,300 Rg. We demonstrate that these regions are out-flowing from the system, and carry a small fraction of material out of the system relative to the implied mass accretion rate. The data suggest that magnetic fields may be an important driving mechanism.