EDP Sciences
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Volume 403, Number 2, May IV 2003
Page(s) 473 - 479
Section Galactic structure and dynamics
DOI http://dx.doi.org/10.1051/0004-6361:20030258

A&A 403, 473-479 (2003)
DOI: 10.1051/0004-6361:20030258

Multiwavelength studies of the Seyfert 1 galaxy NGC 7469 I. Far UV observations with FUSE

G. A. Kriss1, 2, A. Blustin3, G. Branduardi-Raymont3, R. F. Green4, J. Hutchings5 and M. E. Kaiser2

1  Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
    e-mail: gak@stsci.edu
2  Center for Astrophysical Sciences, Johns Hopkins University, Baltimore, MD 21218-2686, USA
3  Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey, RH5 6NT, UK
4  Kitt Peak National Observatory, National Optical Astronomy Observatories, PO Box 26732, 950 North Cherry Ave., Tucson, AZ 85726-6732, USA
    e-mail: rgreen@noao.edu
5  Dominion Astrophysical Observatory, National Research Council of Canada, Victoria, BC, V8X 4M6, Canada
    e-mail: john.hutchings@hia.nrc.ca

(Received 23 December 2002 / Accepted 14 February 2003 )

We obtained far-ultraviolet spectra of the Seyfert 1 galaxy NGC 7469 using the Far Ultraviolet Spectroscopic Explorer on 1999 December 6. Our spectra cover the wavelength range 990-1187 Å with a resolution of ~ 0.05 Å. We see broad emission lines of C III, N III, O VI, and He II as well as intrinsic absorption lines in the O VI $\lambda\lambda1032,1038$ resonance doublet. The absorption arises in two distinct kinematic components at systemic velocities of -569 km s -1 and -1898 km s -1. Both components are very highly ionized - no significant Ly $\beta$ absorption is present. The higher blueshift component is not quite saturated, and it has a total O VI column density of $8 \times 10^{14}~\rm cm^{-2}$. It covers more than 90% of the continuum and broad-line emission. The lower blueshift component is heavily saturated and covers only ~ 50% of the continuum and broad-line emission. It too has a column density of $8 \times 10^{14}~\rm cm^{-2}$, but this is less certain due to the high saturation. We set an upper limit of < $1.5 \times 10^{18}~\rm cm^{-2}$ on the O VI column density of this component. Its line depth is consistent with coverage of only the continuum, and thus this component may lie interior to the broad emission-line gas. The component at -569 km s -1 has a velocity comparable to the high-ionization X-ray absorption lines seen in the XMM-Newton grating spectrum of NGC 7469, and photoionization models show that the observed column densities of O VI and H I are compatible with their formation in the same gas as that causing the X-ray absorption. The gas at -1898 km s -1 has lower ionization and column density, and no significant X-ray absorption is associated with it.

Key words: galaxies: active -- galaxies: individual (NGC 7469) -- galaxies: quasars: absorption lines -- galaxies: Seyfert -- ultraviolet: galaxies -- X-rays: galaxies

Offprint request: G. A. Kriss, gak@stsci.edu

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