IC 3639 - A new bona fide Compton thick AGN unveiled by NuSTAR

Abstract

We analyse 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 $3.6\times 10^{24}$ cm${}^{-2}$, unconstrained at the upper end. We further find an intrinsic 2-10 keV luminosity of ${\text{log}}_{10}(L_{\text{2-10 keV}}{\text{[erg s}}^{-1}])=43.4_{-1.1}^{+0.6}$ to 90% confidence, almost 400 times the observed flux, and consistent with various multi-wavelength diagnostics. Such a high intrinsic to observed flux ratio in addition to an Fe-K$\alpha$ fluorescence line equivalent width exceeding 2 keV is extreme amongst known bona fide CTK AGN, which we suggest are both due to the high level of obscuration present around IC 3639. Our study demonstrates that broadband spectroscopic modelling with NuSTAR enables large corrections for obscuration to be carried out robustly, and emphasises the need for improved modelling of AGN tori showing intense iron fluorescence.

Accepted for publication in the The Astrophysical Journal, 26/10/2016

References in corpus (25)

• The synthesis of the cosmic X-ray background in the Chandra and XMM-Newton era
• Toward the Standard Population Synthesis Model of the X-Ray Background: Evolution of X-Ray Luminosity and Absorption Functions of Active Galactic Nuclei Including Compton-Thick Populations
• An XMM-Newton survey of broad iron lines in Seyfert galaxies
• On the X-ray, optical emission line and black hole mass properties of local Seyfert galaxies
• Cosmic X-ray Surveys of Distant Active Galaxies: The Demographics, Physics, and Ecology of Growing Supermassive Black Holes
• High resolution mid-infrared spectroscopy of ultraluminous infrared galaxies
• The X-Ray to Mid-Infrared Relation of AGN at High Luminosity
• The 2-79 keV X-ray Spectrum of the Circinus Galaxy with NuSTAR, XMM-Newton and Chandra: a Fully Compton-Thick AGN
• Spitzer/IRS 5-35 um Low-Resolution Spectroscopy of the 12 um Seyfert Sample
• The mid IR -- hard X-ray correlation in AGN and its implications for dusty torus models
• The NuSTAR View of Nearby Compton-thick AGN: The Cases of NGC 424, NGC 1320 and IC 2560
• Revisiting the relationship between 6 μm and 2-10 keV continuum luminosities of AGN
• NuSTAR and XMM-Newton Observations of NGC 1365: Extreme Absorption Variability and a Constant Inner Accretion Disk
• Iron K$\alpha$ emission in type-I and type-II Active Galactic Nuclei
• The variable hard X-ray emission of NGC4945 as observed by NuSTAR
• NuSTAR unveils a Compton-thick Type 2 quasar in Mrk 34
• Determining the covering factor of Compton-thick active galactic nuclei with NuSTAR
• Broadband Observations of the Compton-thick Nucleus of NGC 3393
• NuSTAR Resolves the First Dual AGN above 10 keV in SWIFT J2028.5+2543
• Constraints on light bending and reflection from the hard X-ray background
• A direct comparison of X-ray spectral models for tori in active galactic nuclei
• A growth-rate indicator for Compton-thick active galactic nuclei
• A Compton thick AGN in the barred spiral NGC 4785
• IC 3639 - A new bona fide Compton thick AGN unveiled by NuSTAR
• On the equivalent width of the Fe K$\alpha$ line produced by a dusty absorber in active galactic nuclei

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• Infrared Spectral Energy Distribution and Variability of Active Galactic Nuclei: Clues to the Structure of Circumnuclear Material
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