The Ionized Gas and Nuclear Environment in NGC 3783. II. Averaged HST/STIS and FUSE Spectra

Authors: Gabel, J.R.6, Crenshaw, D.M.5, Kraemer, S.6, Brandt, W.N.1, George, I.M.3,4, Netzer, H.2, Hamann, F.W.7, Kaiser, M.E.8, Kaspi, S.1,2, Koratkar, A.9, Kriss, G.A.8,9, Mathur, S.10, Mushotzky, R.F.3, Nandra, K.3,11, Peterson, B.M.10, Shields, J.C.12, Turner, T.J.3,4, Zheng, W.8,
Affiltns: 1Penn State Univ, 2Tel Aviv University, 3 LHEA, NASA/GSFC, 4 JCA, UMBC, 5 Georgia State University, 6 Catholic University of America, 7Univ. Florida, 8Johns Hopkins Univ, 9STScI, 10Ohio State Univ, 11 USRA, 12Ohio Univ
Journal: ApJ, 583, 178
Publn Date: 2003 Jan 20

Summary

We present observations of the intrinsic absorption in the Seyfert 1 galaxy NGC 3783 obtained with the STIS/HST and FUSE. We have coadded multiple STIS and FUSE observations to obtain a high S/N averaged spectrum spanning 905-1730 A. The averaged spectrum reveals absorption in O VI, N V, C IV, N III, C III and the Lyman lines up to LyE in the three blueshifted kinematic components previously detected in the STIS spectrum (at radial velocities of -1320, -724, and -548 km/s). The highest velocity component exhibits absorption in Si IV. We also detect metastable C III* in this component, indicating a high density in this absorber. We separate the individual covering factors of the continuum and emission-line sources as a function of velocity in each kinematic component using the LyA and LyB lines. Additionally, we find that the continuum covering factor varies with velocity within the individual kinematic components, decreasing smoothly in the wings of the absorption by at least 60%. The covering factor of Si IV is found to be less than half that of H I and N V in the high velocity component. Additionally, the FWHM of N III and Si IV are narrower than the higher ionization lines in this component. These results indicate there is substructure within this absorber. We derive a lower limit on the total column (NH 1019 cm-2) and ionization parameter (U 0.005) in the low ionization subcomponent of this absorber. The metastable-to-total C III column density ratio implies ne~ 109 cm-3 and an upper limit on the distance of the absorber from the ionizing continuum of R lteq 8x1017 cm.

Figures: Fig1 Fig2 Fig3a Fig3b Fig3c Fig4 Fig5a Fig5b

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See Also

The Ionized Gas and Nuclear Environment in NGC 3783 papers:
I Time-averaged 900 ks Chandra Grating Spectroscopy
Kaspi, S., et al., 2002, ApJ, 574, 643
II Averaged HST/STIS and FUSE Spectra
Gabel, J.R., et al., 2003, ApJ, 583, 178
III Detection of a Decreasing Radial Velocity in an Intrinsic UV Absorber
Gabel, J.R., et al., 2003, ApJ, 595, 120
IV Variability and Modeling the 900 ks Chandra Spectrum
Netzer, H., et al., 2003, ApJ, 599, 933
V Variability and Modeling of the Intrinsic Ultraviolet Absorption
Gabel, J.R., 2005, ApJ, submitted