Intrinsic Absorption in the Spectrum of NGC 7469: Simultaneous Chandra, FUSE, and STIS Observations

• Published in: The Astrophysical journal Vol. 634; no. 1; pp. 193 - 209
• Main Authors: Scott, Jennifer E, Kriss, Gerard A, Lee, Julia C, Quijano, Jessica Kim, Brotherton, Michael, Canizares, Claude R, Green, Richard F, Hutchings, John, Kaiser, Mary Elizabeth, Marshall, Herman, Oegerle, William, Ogle, Patrick, Zheng, Wei
• Format: Journal Article
• Language: English
• Published: Chicago, IL IOP Publishing 20-11-2005; University of Chicago Press
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; Quasars; galaxies: Seyfert; X-ray galaxies; ultraviolet: galaxies; quasars: absorption lines; X-rays: galaxies; Cosmic x-ray sources; Active galaxies; Seyfert galaxies; Absorption line; galaxies: active; galaxies: individual (NGC 7469); Absorption spectra
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1086/496911

We present simultaneous X-ray, far-ultraviolet, and near-ultraviolet spectra of the Seyfert 1 galaxy NGC 7469 obtained with the Chandra X-Ray Observatory, the Far Ultraviolet Spectroscopic Explorer, and the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. Previous nonsimultaneous observations of this galaxy found two distinct UV absorption components, at -560 and -1900 km s super(-1), with the former as the likely counterpart of the X-ray absorber. We confirm these two absorption components in our new UV observations, in which we detect prominent O VI, Lya, N V, and C IV absorption. In our Chandra spectrum we detect O VIII emission, but no significant O VIII or O VII absorption. We also detect a prominent Fe Ka emission line in the Chandra spectrum, as well as absorption due to hydrogen-like and helium-like neon, magnesium, and silicon at velocities consistent with the -560 km s super(-1) UV absorber. The FUSE and STIS data reveal that the H I and C IV column densities in this UV- and X-ray-absorbing component have increased over time, as the UV continuum flux decreased. We use measured H I, N V, C IV, and O VI column densities to model the photoionization state of both absorbers self-consistently. We confirm the general physical picture of the outflow in which the low-velocity component is a highly ionized, high-density absorber with a total column density of 10 super(20) cm super(-2), located near the broad emission-line region, although due to measurable columns of N V and C IV, we assign it a somewhat smaller ionization parameter than found previously, U 6 1. The high-velocity UV component is of lower density, log N = 18.6, and likely resides farther from the central engine, as we find its ionization parameter to be U = 0.08.