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Mike Crenshaw (Georgia State University) Steve Kraemer (Catholic University of America) Jack Gabel (University of Colorado) NGC 4151 Mass Outflows from AGN in Emission and Absorption
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UV/X-ray Observations of NGC 4151 Six HST/STIS echelle observations (0.2'' x 0.2'’) of central emission- line knot (including nucleus): 1999 July - 2002 May Simultaneous HST, FUSE, and CXO observations in 2002 May (see Kraemer et al. 2005, ApJ, 633, 693 for more on X-ray observations) NGC 4151 [O III] Image
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History of UV Continuum Variations (~21 Years) IUE: black pluses HUT: red diamonds FOS: green triangles STIS: blue x’s STIS observations taken at moderate to low flux levels
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Absorption Components in STIS and FUSE Spectra A, C, D+E, E are intrinsic; B is Galactic; F, F are host galaxy. D+E (v r = -500 km s -1 ) responsible for bulk of UV and X-ray absorption.
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(Kraemer et al. 2006, in preparation) D+E varies strongly in the low-ionization lines (e.g., Si II) D+E in 2002 is much weaker than expected from ionization changes Variability in C IV Region
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Variability of D+E Absorption (1999 - 2002) EW of low-ionization lines generally anti-correlated with continuum ionization changes (high-ionization lines are saturated) Low EW in last observation indicates change in column density. transverse motion: v T ≥ 1250 km s -1
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blue - narrow green - intermediate Emission-Line Profiles at Low Flux Levels He II profile has two components (broad component not detected): narrow: 260 km s -1 FWHM, intermediate: 1150 km s -1 FWHM He II
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Emission-Line Profiles at Low Flux Levels Fit to C IV profile using He II components (plus broad-line profile) D+E absorbs intermediate component self absorption? (P-Cygni like) likely the absorber in emission blue - narrow green - intermediate red - broad C IV
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Photoionization Models: 2002 STIS, FUSE, CXO Observations D+Eb responsible for most of the metastable C III. distance ≈ 0.1pc D+Ea is responsible for high-ionization UV lines and most of the X-ray absorption, and must screen D+Eb distance ≤ 0.1pc D+Ec needed for low C los of P V, etc. (distance unknown) D+EaD+EbD+Ec Log U-0.26-1.66-1.08 Log N H 22.520.821.6 Log n H 6.757.65--- C los ~10.80.5 C global 0.810.380.35
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Conclusions The outflowing UV absorbers in NGC 4151 vary as a result of both changing ionization and motion across the line of sight. Component D+E is responsible for the bulk of the UV and X- ray absorption, and has several physical subcomponents (a-c). Most of D+E is only ~0.1 pc from the central source (compared to tens of pcs for many UV/X-ray absorbers). D+E (at v r = 500 km s-1) has a transverse velocity ≥ 1250 km s -1, similar to the rotation velocity at 0.1 pc (720 km s -1 ). We have detected D+E in emission, which yields a global covering factor of 0.35 - 0.8. This component provides the best case for a rotating accretion disk wind in a Seyfert galaxy.
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