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Title: An extended XMM–Newton observation of the Seyfert galaxy NGC 4051 – III. Fe K emission and absorption
Authors: Pounds, Kenneth Alwyne
Vaughan, Simon
First Published: 11-Jun-2012
Publisher: Oxford University Press (OUP)
Citation: Monthly Notices of the Royal Astronomical Society, 2012, 423, pp. 165-175 (11)
Abstract: An extended XMM–Newton observation of the Seyfert 1 galaxy NGC 4051 in 2009 detected a photoionized outflow with a complex absorption-line velocity structure and a broad correlation of velocity with ionization parameter, shown by Pounds & Vaughan to be consistent with a highly ionized, high-velocity wind running into the interstellar medium or previous ejecta, losing much of its kinetic energy in the resultant strong shock. In this paper, we examine the Fe K spectral region in more detail and find support for two distinct velocity components in the highly ionized absorber, with values corresponding to the putative fast wind (∼0.12c) and the post-shock flow (v∼ 5000–7000 km s[Superscript: −1]). The Fe K absorption-line structure is seen to vary on a orbit-to-orbit time-scale, apparently responding to both a short-term increase in ionizing flux and – perhaps more generally – to changes in the soft X-ray (and simultaneous ultraviolet) luminosity. The latter result is particularly interesting in providing independent support for the existence of shocked gas being cooled primarily by Compton scattering of accretion disc photons. The Fe K emission is represented by a narrow fluorescent line from near-neutral matter, with a weak red wing modelled here by a relativistic diskline. The narrow line flux is quasi-constant throughout the 45-d 2009 campaign, but is resolved, with a velocity width consistent with scattering from a component of the post-shock flow. Evidence for a P Cygni profile is seen in several individual orbit spectra for resonance transitions in both Fe xxv and Fe xxvi.
DOI Link: 10.1111/j.1365-2966.2012.20753.x
ISSN: 0035-8711
eISSN: 1365-2966
Version: Publisher Version
Status: Peer-reviewed
Type: Journal Article
Rights: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2012 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. Deposited with reference to the publisher’s archiving policy available on the SHERPA/RoMEO website.
Appears in Collections:Published Articles, Dept. of Physics and Astronomy

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