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Variable Nature of Magnetically-Driven Ultra-Fast Outflows

Fukumura, Keigo and Kazanas, Demosthenes and Shrader, Chris and Behar, Ehud and Tombesi, Francesco and Contopoulos, Ioannis (2018) Variable Nature of Magnetically-Driven Ultra-Fast Outflows. Astrophysical Journal Letters, 864 (2). Art. No. L27. ISSN 2041-8213. doi:10.3847/2041-8213/aadd10.

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Among a number of active galactic nuclei that drive ionized outflows in X-rays, a low-redshift (z = 0.184) quasar, PDS 456, is long known to exhibit one of the exemplary ultra-fast outflows (UFOs). However, the physical process of acceleration mechanisms is yet to be definitively constrained. In this work, we model the variations of the Fe K UFO properties in PDS 456 over many epochs in X-ray observations in the context of magnetohydrodynamic (MHD) accretion disk winds employed in our earlier studies of similar X-ray absorbers. We applied the model to the 2013/2014 XMM-Newton/NuSTAR spectra to determine the UFO's condition; namely, velocity, ionization parameter, column density, and equivalent width (EW). Under some provisions on the dependence of X-ray luminosity on the accretion rate applicable to near-Eddington state, our photoionization calculations, coupled to a 2.5-dimensional MHD-driven wind model, can further reproduce the observed correlations of the UFO velocity and the anticorrelation of its EW with the X-ray strength of PDS 456. This work demonstrates that UFOs, even without radiative pressure, can be driven as an extreme case purely by magnetic interaction while also producing the observed spectrum and correlations.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Fukumura, Keigo0000-0001-5709-7606
Kazanas, Demosthenes0000-0002-7435-7809
Tombesi, Francesco0000-0002-6562-8654
Contopoulos, Ioannis0000-0001-6890-4143
Additional Information:© 2018 The American Astronomical Society. Received 2018 June 6; revised 2018 July 26; accepted 2018 August 27; published 2018 September 6. We are grateful to the anonymous referee for helpful comments on the original manuscript and James Reeves for providing us with the XMM-Newton/NuSTAR spectrum. K.F. thanks Alex Sanner for his assistance on wind visualization calculations. This work is supported in part by NASA/ADAP (NNH15ZDA001N-ADAP) and Chandra Cycle 17 archive proposal (17700504).
Subject Keywords:accretion, accretion disks – galaxies: individual (PDS 456) – magnetohydrodynamics (MHD) – methods: numerical – quasars: absorption lines
Issue or Number:2
Record Number:CaltechAUTHORS:20180828-095719590
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Official Citation:Keigo Fukumura et al 2018 ApJL 864 L27
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:89202
Deposited By: Joy Painter
Deposited On:28 Aug 2018 17:17
Last Modified:16 Nov 2021 00:33

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