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

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

Corresponding author: G. A. Kriss, gak@stsci.edu

Received: 23 December 2002
Accepted: 14 February 2003

Abstract

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  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 Lyβ absorption is present. The higher blueshift component is not quite saturated, and it has a total O vi column density of . 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 , but this is less certain due to the high saturation. We set an upper limit of < 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.