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NuSTAR Reveals the Comptonizing Corona of the Broad-line Radio Galaxy 3C 382

Ballantyne, D. R. and Bollenbacher, J. M. and Brenneman, L. W. and Madsen, K. K. and Baloković, M. and Boggs, S. E. and Christensen, F. E. and Craig, W. W. and Gandhi, P. and Hailey, C. J. and Harrison, F. A. and Lohfink, A. M. and Marinucci, A. and Markwardt, C. B. and Stern, D. and Walton, D. J. and Zhang, W. W. (2014) NuSTAR Reveals the Comptonizing Corona of the Broad-line Radio Galaxy 3C 382. Astrophysical Journal, 794 (1). Art. No. 62. ISSN 0004-637X. doi:10.1088/0004-637X/794/1/62.

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Broad-line radio galaxies (BLRGs) are active galactic nuclei that produce powerful, large-scale radio jets, but appear as Seyfert 1 galaxies in their optical spectra. In the X-ray band, BLRGs also appear like Seyfert galaxies, but with flatter spectra and weaker reflection features. One explanation for these properties is that the X-ray continuum is diluted by emission from the jet. Here, we present two NuSTAR observations of the BLRG 3C 382 that show clear evidence that the continuum of this source is dominated by thermal Comptonization, as in Seyfert 1 galaxies. The two observations were separated by over a year and found 3C 382 in different states separated by a factor of 1.7 in flux. The lower flux spectrum has a photon-index of Γ = 1.68^)+0.03_(−0.02), while the photon-index of the higher flux spectrum is Γ = 1.78^(+0.02)_(−0.03). Thermal and anisotropic Comptonization models provide an excellent fit to both spectra and show that the coronal plasma cooled from kT_e = 330 ± 30 keV in the low flux data to 231^(+50)_(−88) keV in the high flux observation. This cooling behavior is typical of Comptonizing corona in Seyfert galaxies and is distinct from the variations observed in jet-dominated sources. In the high flux observation, simultaneous Swift data are leveraged to obtain a broadband spectral energy distribution and indicates that the corona intercepts ~10% of the optical and ultraviolet emitting accretion disk. 3C 382 exhibits very weak reflection features, with no detectable relativistic Fe Kα line, that may be best explained by an outflowing corona combined with an ionized inner accretion disk.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Ballantyne, D. R.0000-0001-8128-6976
Madsen, K. K.0000-0003-1252-4891
Baloković, M.0000-0003-0476-6647
Boggs, S. E.0000-0001-9567-4224
Christensen, F. E.0000-0001-5679-1946
Gandhi, P.0000-0003-3105-2615
Harrison, F. A.0000-0003-2992-8024
Markwardt, C. B.0000-0001-9803-3879
Stern, D.0000-0003-2686-9241
Walton, D. J.0000-0001-5819-3552
Zhang, W. W.0000-0002-1426-9698
Additional Information:© 2014 The American Astronomical Society. Received 2014 May 13; accepted 2014 August 14; published 2014 September 24. We thank the referee for a helpful report that improved the paper. This work was supported under NASA Contract No. NNG08FD60C, and 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 theASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA). This work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester. This research has made use of data, software and/or web tools obtained from NASA’s High Energy Astrophysics Science Archive Research Center (HEASARC), a service of Goddard Space Flight Center and the Smithsonian Astrophysical Observatory. D.R.B. acknowledges support from NASA ADAP grant NNX13AI47G and NSF award AST 1008067. A.M. acknowledge financial support from Italian Space Agency under grant ASI/INAF I/037/12/0-011/13 and from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n.312789. M.B. acknowledges support from the International Fulbright Science and Technology Award.
Group:NuSTAR, Space Radiation Laboratory
Funding AgencyGrant Number
Agenzia Spaziale Italiana (ASI)ASI/INAF I/037/ 12/0-011/13
European UnionFP7/2007-2013
International Fulbright Science and Technology AwardUNSPECIFIED
Istituto Nazionale di Astrofisica (INAF)UNSPECIFIED
Subject Keywords:accretion, accretion disks; galaxies: active; galaxies: individual (3C 382); galaxies: nuclei; X-rays: galaxies
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2014-29
Issue or Number:1
Record Number:CaltechAUTHORS:20141106-132347774
Persistent URL:
Official Citation:NuSTAR Reveals the Comptonizing Corona of the Broad-line Radio Galaxy 3C 382 D. R. Ballantyne et al. 2014 ApJ 794 62
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:51377
Deposited On:06 Nov 2014 23:46
Last Modified:10 Nov 2021 19:10

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