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Title: The 2-79 keV X-ray Spectrum of the Circinus Galaxy with NuSTAR, XMM-Newton and Chandra: a Fully Compton-Thick Active Galactic Nucleus

Journal Article · · The Astrophysical Journal (Online)
 [1];  [2]; ORCiD logo [3];  [4];  [5];  [6];  [7];  [8];  [9];  [10];  [6];  [4];  [11];  [4];  [12];  [4];  [7];  [13];  [4];  [14] more »;  [14];  [15]; ORCiD logo [4];  [16];  [17];  [18];  [19] « less
  1. Univ. Catolica de Chile, Santiago (Chile); Univ. de Valparaiso, Valparaiso (Chile)
  2. Univ. Catolica de Chile, Santiago (Chile); Space Science Institute, Boulder, CO (United States)
  3. ASDC-ASI, Roma (Italy); INAF Osservatorio Astronomico di Roma, Monte Porzio Catone (RM) (Italy)
  4. California Inst. of Technology (CalTech), Pasadena, CA (United States)
  5. ETH Zurich, Zurich (Switzerland)
  6. Univ. of California, Berkeley, CA (United States)
  7. The Pennsylvania State Univ., University Park, PA (United States)
  8. Max-Planck-Institut fur extraterrestrische Physik, Garching bei Munchen (Germany)
  9. Danish Technical Univ., Lyngby (Denmark)
  10. INAF-Osservatorio Astronomico di Bologna, Bologna (Italy)
  11. Durham Univ., Durham (United Kingdom)
  12. Columbia Univ., New York, NY (United States)
  13. SLAC National Accelerator Lab., Menlo Park, CA (United States)
  14. Univ. degli Studi Roma Tre, Roma (Italy)
  15. Univ. Catolica de Chile, Santiago (Chile); Univ. of Maryland, College Park, MD (United States)
  16. European Space Astronomy Centre (ESAC), Madrid (Spain)
  17. Univ. de Concepcion, Concepcion (Chile)
  18. Yale Univ., New Haven, CT (United States)
  19. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)
+ Show Author Affiliations

Here, the Circinus galaxy is one of the closest obscured active galactic nuclei (AGNs), making it an ideal target for detailed study. Combining archival Chandra and XMM-Newton data with new NuSTAR observations, we model the 2-79 keV spectrum to constrain the primary AGN continuum and to derive physical parameters for the obscuring material. Chandra's high angular resolution allows a separation of nuclear and off-nuclear galactic emission. In the off-nuclear diffuse emission, we find signatures of strong cold reflection, including high equivalent-width neutral Fe lines. This Compton-scattered off-nuclear emission amounts to 18% of the nuclear flux in the Fe line region, but becomes comparable to the nuclear emission above 30 keV. The new analysis no longer supports a prominent transmitted AGN component in the observed band. We find that the nuclear spectrum is consistent with Compton scattering by an optically thick torus, where the intrinsic spectrum is a power law of photon index Γ = 2.2-2.4, the torus has an equatorial column density of N H = (6-10) × 1024 cm–2, and the intrinsic AGN 2-10 keV luminosity is (2.3-5.1) × 1042 erg s–1. These values place Circinus along the same relations as unobscured AGNs in accretion rate versus Γ and LX versus L IR phase space. NuSTAR's high sensitivity and low background allow us to study the short timescale variability of Circinus at X-ray energies above 10 keV for the first time. Here, the lack of detected variability favors a Compton-thick absorber, in line with the spectral fitting results.

Research Organization:
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC); National Aeronautics and Space Administration (NASA)
Grant/Contract Number:
AC02-76SF00515
OSTI ID:
1165906
Report Number(s):
SLAC-PUB-16153; arXiv:1406.3345
Journal Information:
The Astrophysical Journal (Online), Vol. 791, Issue 2; ISSN 1538-4357
Publisher:
Institute of Physics (IOP)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 98 works
Citation information provided by
Web of Science

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Cited By (27)

X-ray spectral and eclipsing model of the clumpy obscurer in active galactic nuclei journal August 2019
Revealing the X-ray variability of AGN with principal component analysis journal December 2014
The subarcsecond mid-infrared view of local active galactic nuclei – II. The mid-infrared–X-ray correlation journal September 2015
PAH features within few hundred parsecs of active galactic nuclei journal June 2017
An Iwasawa–Taniguchi effect for Compton-thick active galactic nuclei journal April 2018
Dissecting the active galactic nucleus in Circinus – II. A thin dusty disc and a polar outflow on parsec scales journal January 2019
The exceptional X-ray evolution of SN 1996cr in high resolution journal October 2019
The black hole X-ray transient Swift J1357.2–0933 as seen with Swift and NuSTAR during its 2017 outburst journal March 2019
THE SOFT STATE OF CYGNUS X-1 OBSERVED WITH NuSTAR : A VARIABLE CORONA AND A STABLE INNER DISK journal July 2016
Long-Term X-Ray Variability of Typical Active Galactic Nuclei in the Distant Universe journal November 2016
The Composite Nature of Dust-obscured Galaxies (DOGs) at z ∼ 2–3 in the COSMOS Field. II. The AGN Fraction journal May 2019
New Spectral Model for Constraining Torus Covering Factors from Broadband X-Ray Spectra of Active Galactic Nuclei journal February 2018
Compton Shoulder Diagnostics in Active Galactic Nuclei for Probing the Metallicity of the Obscuring Compton-thick Tori journal November 2018
Circumnuclear Multiphase Gas in the Circinus Galaxy. II. The Molecular and Atomic Obscuring Structures Revealed with ALMA journal October 2018
Deep Chandra Observations of ESO 428-G014. IV. The Morphology of the Nuclear Region in the Hard Continuum and Fe K α Line journal January 2019
XCLUMPY: X-Ray Spectral Model from Clumpy Torus and Its Application to the Circinus Galaxy journal May 2019
Measuring the Obscuring Column of a Disk Megamaser AGN in a Nearby Merger journal September 2019
NuSTAR Uncovers an Extremely Local Compton-thick AGN in NGC 4968 journal December 2019
BAT AGN Spectroscopic Survey. V. X-Ray Properties of the Swift /BAT 70-month AGN Catalog journal December 2017
Deep Chandra Observations of ESO 428-G014. IV. The Morphology of the Nuclear Region in the Hard Continuum and Fe Kα Line text January 2019
The subarcsecond mid-infrared view of local active galactic nuclei: II. The mid-infrared--X-ray correlation text January 2015
The Soft State of Cygnus X-1 Observed with NuSTAR: A Variable Corona and a Stable Inner Disk text January 2016
BAT AGN Spectroscopic Survey - V. X-ray properties of the Swift/BAT 70-month AGN catalog text January 2017
Compton Shoulder Diagnostics in Active Galactic Nuclei for Probing the Metalicity of the Obscuring Compton-Thick Tori text January 2018
Dissecting the active galactic nucleus in Circinus -- II. A thin dusty disc and a polar outflow on parsec scales text January 2019
The black hole X-ray transient Swift J1357.2-0933 as seen with Swift and NuSTAR during its 2017 outburst text January 2019
X-ray spectral and eclipsing model of the clumpy obscurer in active galactic nuclei text January 2019

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Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
Astrophysics
ASTRO
GRQC
axies: active
galaxies: individual (Circinus)
galaxies: Seyfert
X-rays: galaxies