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IC 3639 - A New Bona Fide Compton-Thick AGN Unveiled By NuSTARWe analyze high-quality NuSTAR observations of the local (z = 0.011) Seyfert 2 active galactic nucleus (AGN) IC 3639, in conjunction with archival Suzaku and Chandra data. This provides the first broadband X-ray spectral analysis of the source, spanning nearly two decades in energy (0.5-30 keV). Previous X-ray observations of the source below 10 keV indicated strong reflection/obscuration on the basis of a pronounced iron fluorescence line at 6.4 keV. The hard X-ray energy coverage of NuSTAR, together with self-consistent toroidal reprocessing models, enables direct broadband constraints on the obscuring column density of the source. We find the source to be heavily Compton-thick (CTK) with an obscuring column in excess of 3.6 x 10(exp 24) cm(exp −2), unconstrained at the upper end. We further find an intrinsic 2-10 keV luminosity of log(sub 10) (L(sub 2-10 keV) [erg s(exp -1)])= 43.4(+0.6/-1.1) to 90% confidence, almost 400 times the observed flux, and consistent with various multiwavelength diagnostics. Such a high ratio of intrinsic to observed flux, in addition to an Fe-K(alpha) fluorescence line equivalent width exceeding 2 keV, is extreme among known bona fide CTK AGNs, which we suggest are both due to the high level of obscuration present around IC 3639. Our study demonstrates that broadband spectroscopic modeling with NuSTAR enables large corrections for obscuration to be carried out robustly and emphasizes the need for improved modeling of AGN tori showing intense iron fluorescence.
Document ID
Document Type
Reprint (Version printed in journal)
Boorman, Peter G.
(Southampton Univ. United Kingdom)
Gandhi, P.
(Southampton Univ. United Kingdom)
Alexander, D. M.
(Durham Univ. United Kingdom)
Annuar, A.
(Durham Univ. United Kingdom)
Ballantyne, D. R.
(Georgia Inst. of Tech. Atlanta, GA, United States)
Bauer, F.
(Pontificia Univ. Catolica de Chile Santiago, Chile)
Boggs, S. E.
(California Univ. Berkeley, CA, United States)
Brandt, W. N.
(Pennsylvania State Univ. University Park, PA, United States)
Brightman, M.
(California Inst. of Tech. Pasadena, CA, United States)
Christensen, F. E.
(Technical Univ. of Denmark Lyngby, Denmark)
Craig, W. W.
(Technical Univ. of Denmark Lyngby, Denmark)
Farrah, D.
(Virginia Polytechnic Inst. and State Univ. Blacksburg, VA, United States)
Hailey, C. J.
(Columbia Univ. New York, NY, United States)
Harrison, F. A.
(Lawrence Livermore National Lab. Livermore, CA, United States)
Hoenig, S. F.
(Southampton Univ. United Kingdom)
Koss, M.
(Eidgenoessische Technische Hochschule Zurich, Switzerland)
LaMassa, S. M.
(Space Telescope Science Inst. Baltimore, MD, United States)
Masini, A.
(Istituto Nazionale di Astrofisica Spaziale e Fisica Cosmica (INAF-IASF) Bologna, Italy)
Ricci, C.
(Pontificia Univ. Catolica de Chile Santiago, Chile)
Risaliti, G.
(Observatorie Astofisico di Arcetri Florence, Italy)
Stern, D.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Zhang, William W.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
July 6, 2017
Publication Date
December 20, 2016
Publication Information
Publication: The Astrophysical Journal
Volume: 833
Issue: 2
ISSN: 0004-637X
Subject Category
Report/Patent Number
Funding Number(s)
Distribution Limits
galaxies: active – galaxies: nuclei – galaxies: Seyfert – techniques: spec

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