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Broadband Observations of the Compton-thick Nucleus of NGC 3393

Koss, Michael J. and Romero-Canizales, C. and Baronchelli, L. and Teng, S. H. and Baloković, M. and Puccetti, S. and Bauer, F. E. and Arévalo, P. and Assef, R. J. and Ballantyne, D. R. and Brandt, W. N. and Brightman, M. and Comastri, A. and Gandhi, P. and Harrison, F. A. and Luo, B. and Schawinski, K. and Stern, D. and Treister, E. (2015) Broadband Observations of the Compton-thick Nucleus of NGC 3393. Astrophysical Journal, 807 (2). Art. No. 149. ISSN 0004-637X.

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We present new Nuclear Spectroscopic Telescope Array (NuSTAR ) and Chandra observations of NGC 3393, a galaxy reported to host the smallest separation dual active galactic nuclei (AGN) resolved in the X-rays. While past results suggested a 150 pc separation dual AGN, three times deeper Chandra imaging, combined with adaptive optics and radio imaging suggest a single, heavily obscured, radio-bright AGN. Using Very Large Array and Very Long Baseline Array data, we find an AGN with a two-sided jet rather than a dual AGN and that the hard X-ray, UV, optical, near-infrared, and radio emission are all from a single point source with a radius <"0.2. We find that the previously reported dual AGN is most likely a spurious detection resulting from the low number of X-ray counts (<160) at 6–7 keV and Gaussian smoothing of the data on scales much smaller than the point-spread function (PSF) (0".25 versus 0″.80 FWHM). We show that statistical noise in a single Chandra PSF generates spurious dual peaks of the same separation (0." 55 ±0 ."07 versus 0."6) and flux ratio (39% ± 9% versus 32% counts) as the purported dual AGN. With NuSTAR, we measure a Compton-thick source (NH 2.2 0.4 10 ± 24 cm^(-2)) with a large torus half-opening angle, 0_(tor) 79 +1/_19° which we postulate results from feedback from strong radio jets. This AGN shows a 2–10 keV intrinsic-to-observed flux ratio of »150 (L_(-10 keV int) 2.6 ± 0.3 10^(erg) s^(-1)- versus L_(2-10 keV int) observed 1.7 ± 0.2 X 10^(41) erg s^(-1). Using simulations, we find that even the deepest Chandra observations would severely underestimate the intrinsic luminosity of NGC 3393 above z > 0.2, but would detect an unobscured AGN of this luminosity out to high redshift (z » 5).

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Koss, Michael J.0000-0002-7998-9581
Puccetti, S.0000-0002-2734-7835
Bauer, F. E.0000-0002-8686-8737
Assef, R. J.0000-0002-9508-3667
Ballantyne, D. R.0000-0001-8128-6976
Brandt, W. N.0000-0002-0167-2453
Comastri, A.0000-0003-3451-9970
Gandhi, P.0000-0003-3105-2615
Harrison, F. A.0000-0003-2992-8024
Luo, B.0000-0002-9036-0063
Stern, D.0000-0003-2686-9241
Additional Information:© 2015. The American Astronomical Society. Received 2015 January 29, accepted for publication 2015 May 5 Published 2015 July 9. We thank Jim Condon, Fred Lo, and Antxon Alberdi for their useful discussion of radio data and astrometry. We thank Harvey Tananbaum and Diab Jerius for useful discussions on the Chandra PSF and using the MARX software. We thank Pepi Fabbiano and Alessandro Paggi for useful discussions of previous NGC 3393 papers. M. K. acknowledges support from the Swiss National Science Foundation (SNSF) through the Ambizione fellowship grant PZ00P2 154799/1. M.K. and K. S. acknowledge support from Swiss National Science Foundation (NSF) grant PP00P2 138979/1. M.K. also acknowledges support for this work was provided by the National Aeronautics and Space Administration through Chandra Award Number AR3-14010X issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060. C.R.C. acknowledges financial support from the ALMA-CONICYT FUND Project 31100004. We also acknowledge support from CONICYT through FONDECYT grant 3150238 (C.R.C.) and from project IC120009 ”Millennium Institute of Astrophysics (MAS) funded by the Iniciativa Científica Milenio del Ministerio Economía, Fomento y Turismo de Chile (C.R.C, F.E.B.). A.C. acknowledges support from the ASI/INAF grant I/037/12/0 011/13 and the Caltech Kingsley visitor program. ST acknowledges support from the NASA postdoctoral fellowship program. Support for the work of ET was provided by the Center of Excellence in Astrophysics and Associated Technologies (PFB 06), by the FONDECYT regular grant 1120061 and by the CONICYT Anillo project ACT1101. M. B. acknowledges support from NASA Headquarters under the NASA Earth and Space Science Fellowship Program, grant NNX14AQ07H. R.J.A. was supported by GeminiCONICYT grant number 32120009. 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 the National Aeronautics and Space Administration. We thank the NuSTAR Operations, Software and Calibration teams for support with the execution and analysis of these observations. This research has made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Science DataCenter (ASDC, Italy) and the California Institute of Technology (USA). This research has made use of software provided by the Chandra X-ray Center (CXC) in the application packages CIAO, ChIPS, and Sherpa. The scientific results reported in this article are based on data obtained from the Chandra Data Archive. This research made use of the XRT Data Analysis Software (XRTDAS), archival data, software and on-line services provided by the ASDC. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. The Cornell Atlas of Spitzer IRS Sources (CASSIS) is a product of the Infrared Science Center at Cornell University, supported by NASA and JPL. We used observations made with the NASA/ESA Hubble Space Telescope, and obtained from the Hubble Legacy Archive, which is a collaboration between the Space Telescope Science Institute (STScI/NASA), the Space Telescope European Coordinating Facility (ST-ECF/ESA), and the Canadian Astronomy Data Centre (CADC/NRC/CSA). This research made use of the Chandra Transmission Grating Catalog and archive ( This paper is based on observations made with the Very Large Array (VLA) and the Very Long Baseline Array (VLBA) of the National Radio Astronomy Observatory (NRAO); the NRAO is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. Facilities: NuSTAR, Swift, CXO, HST (NICMOS, UVIS, WFC3), Keck:II (NIRC2), Spitzer, VLBA, VLA, UH:2.2m, PS1, XMM, Suzaku, BeppoSAX
Group:NuSTAR, Space Radiation Laboratory
Funding AgencyGrant Number
Swiss National Science Foundation (SNSF)PZ00P2 154799/1
Swiss National Science Foundation (SNSF)PP00P2 138979/1
Comisión Nacional de Investigación Científica y Tecnológica (CONICYT)31100004
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)3150238
Iniciativa Científica Milenio (ICM) del Ministerio de EconomíaIC120009
Agenzia Spaziale Italiana (ASI)I/037/12/0 011/13
Center of Excellence in Astrophysics and Associated Technologies PFB 06
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)1120061
Comisión Nacional de Investigación Científica y Tecnológica (CONICYT)ACT1101
Comisión Nacional de Investigación Científica y Tecnológica (CONICYT)32120009
Istituto Nazionale di Astrofisica (INAF)UNSPECIFIED
Non-Subject Keywords:galaxies: active — galaxies: Seyfert—X-rays:galaxies— galaxies:individual (NGC 3393)
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2015-08
Record Number:10.1088/0004-637X/807/2/149
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:59144
Deposited By: Joy Painter
Deposited On:05 Aug 2015 23:53
Last Modified:21 Mar 2019 18:59

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