Is The Fe M-shell Absorber Part of The Outflow in Active Galactic Nuclei?

Abstract

The X-ray emission of many active galactic nuclei (AGNs) is absorbed between 15 and 17 Angstrom by means of unresolved (inner-shell) transition arrays (UTAs) of Fe M-shell ions. The outflow velocities implied by the Doppler shifts of the individual UTAs in the spectrum have never before been measured. Thus, the Fe-M absorber has been commonly assumed to be part of the ionized AGN outflow, whose velocities are readily obtained from more easily measured spectral lines. The best spectrum of Fe-M absorption is available from the integrated 900 ks Chandra HETGS observations of NGC 3783, in which some Fe-M ions are clearly resolved. We measure the velocities of the individual Fe-M ions in NGC 3783 for the first time. Surprisingly, we find that the Fe-M absorber, most noticeably Fe${}^{+8}$, Fe${}^{+9}$, and Fe${}^{+10}$, is not outflowing at the same velocity as the previously known wind. In fact, it appears to be stationary and therefore not part of the outflow at all. It could, alternatively, be ascribed to the skin of the dusty torus. This reduces appreciably the mass loss rate estimated for the NGC 3783 outflow and perhaps for other similar sources as well, in which the various Fe-M ions are not resolved.

To be published in ApJ

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• Inner-shell Absorption Lines of Fe~VI-- Fe~XVI: A Many-body Perturbation Theory Approach
• Warm Absorbers in X-rays (WAX), a comprehensive high resolution grating spectral study of a sample of Seyfert Galaxies: II. Warm Absorber dynamics and feedback to galaxies
• Extended relativistic configuration interaction and many-body perturbation calculations of spectroscopic data for the $n\le 6$ configurationsin ne-like ions between Cr XV and Kr XXVII
• Imprints of a high velocity wind on the soft x-ray spectrum of PG 1211+143
• Near L-edge photoionization of triply charged iron ions
• X-Ray Absorption Analysis of MCG-6-30-15: Discerning Three Kinematic Systems
• X-Ray Absorption Analysis of NGC3516: Appearance of Fast Components with Increased Source Flux