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The ultrafast outflow of WKK 4438: Suzaku and NuSTAR X-ray spectral analysis

Jiang, Jiachen and Walton, Dominic J. and Parker, Michael L. and Fabian, Andrew C. (2018) The ultrafast outflow of WKK 4438: Suzaku and NuSTAR X-ray spectral analysis. Monthly Notices of the Royal Astronomical Society, 481 (1). pp. 639-644. ISSN 0035-8711. doi:10.1093/mnras/sty2344.

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Previous X-ray spectral analysis has revealed an increasing number of active galactic nuclei (AGNs) with high accretion rates where an outflow with a mildly relativistic velocity originates from the inner accretion disc. Here we report the detection of a new ultrafast outflow (UFO) with a velocity of v_(out) = 0.319^(+0.005)_(−0.008)c in addition to a relativistic disc reflection component in a poorly studied NLS1 WKK 4438, based on archival NuSTAR and Suzaku observations. The spectra of both Suzaku and NuSTAR observations show an Fe XXVI absorption feature and the Suzaku data also show evidence for an Ar XVIII with the same blueshift. A supersolar argon abundance (Z′_(Ar) > 6Z⊙) and a slight iron overabundance (Z′_(Fe) = 2.6^(+1.9)_(−2.0) Z⊙) are found in our spectral modelling. Based on Monte Carlo simulations, the detection of the UFO is estimated to be at around 3σ significance. The fast wind most likely arises from a radius of ≥20rg away from the central black hole. The disc is accreting at a high Eddington ratio (L_(bol) = 0.4−0.7L_(Edd)). The mass outflow rate of the UFO is comparable with the disc mass inflow rate (M_(out) > 30% M_(in)), assuming a maximum covering factor. The kinetic power of the wind might not be high enough to have an influence on AGN feedback (E_(wind)/L_(bol) ≈ 3−5 per cent) due to a relatively small column density (12^(+9)_(−4) × 10^(22) cm^(−2)). However, note that both the inferred velocity and the column density could be lower limits owing to the low viewing angle (i=23^(+3)_(−2)∘).

Item Type:Article
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URLURL TypeDescription Paper
Jiang, Jiachen0000-0002-9639-4352
Walton, Dominic J.0000-0001-5819-3552
Parker, Michael L.0000-0002-8466-7317
Fabian, Andrew C.0000-0002-9378-4072
Additional Information:© 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model ( Accepted 2018 August 23. Received 2018 August 22; in original form 2018 May 3. Published: 28 August 2018. J.J. acknowledges support by the Cambridge Trust and the Chinese Scholarship Council Joint Scholarship Programme (201604100032). D.J.W. acknowledges support from an Science and Technology Facilities Council Ernest Rutherford fellowship. M.L.P. is supported by a European Space Agency (ESA) research fellowship. A.C.F. acknowledges support by the European Research Council Advanced Grant 340442. This work made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by NASA, and data obtained from the Suzaku satellite, a collaborative mission between the space agencies of Japan (JAXA) and the USA (NASA). This research has made use of the NuSTAR Data Analysis Software (NUSTARDAS) jointly developed by the ASI Science Data Center and the California Institute of Technology.
Subject Keywords:accretion, accretion discs – black hole physics – galaxies: Seyfert –X-rays: galaxies
Issue or Number:1
Record Number:CaltechAUTHORS:20180828-093504739
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Official Citation:Jiachen Jiang (姜嘉陈), Dominic J Walton, Michael L Parker, Andrew C Fabian; The ultrafast outflow of WKK 4438: Suzaku and NuSTAR X-ray spectral analysis, Monthly Notices of the Royal Astronomical Society, Volume 481, Issue 1, 21 November 2018, Pages 639–644,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:89197
Deposited By: Joy Painter
Deposited On:28 Aug 2018 16:51
Last Modified:16 Nov 2021 00:33

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