AAS 199th meeting, Washington, DC, January 2002
Session 99. AGN - Narrow Line and Broad Line
Display, Wednesday, January 9, 2002, 9:20am-6:30pm, Exhibit Hall

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[99.01] Constraining the Location and Physical Conditions of Intrinsic NAL Gas in QSOs

N.A. Bond, R. Ganguly, J.C. Charlton (The Pennsylvania State University)

An important question in the analysis of QSO-intrinsic narrow absorption line (NAL) gas is: Where is it? We lay further groundwork for constraining the physical conditions and geometry of NALs, considering different physical locations for the gas in the context of the accretion-disk/wind scenario. As a motivation for this work, we focus on the observed correlation between \alphaox (the optical--x-ray spectral slope) and the equivalent width of associated C IV absorption (Brandt et. al 2000, ApJ, 528, 637). Brandt et al. suggest that this correlation is driven by absorption, with more absorption in soft X-rays (i.e,. from oxygen edges) implying more absorption in the UV. We present Monte Carlo simulations of NAL clouds surrounding a QSO. Using the known properties of NALs, we attempt to constrain the conditions under which the EWCIV-\alphaox correlation can occur. Our analysis includes a tuning of the parameters of the cloud velocity, position, and number distributions along the line of sight to the QSO and we compare these derived distributions to those expected from standard QSO models.

We acknowledge support from the National Science Foundation and from NASA through the LTSA program.

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