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Coronal Properties of the Seyfert 1.9 Galaxy MCG-05-23-016 Determined from Hard X-Ray Spectroscopy with NuSTAR

Baloković, M. and Matt, G. and Harrison, F. A. and Zoghbi, A. and Ballantyne, D. R. and Boggs, S. E. and Christensen, F. E. and Craig, W. W. and Esmerian, C. J. and Fabian, A. C. and Fürst, F. and Hailey, C. J. and Marinucci, A. and Parker, M. L. and Reynolds, C. S. and Stern, D. and Walton, D. J. and Zhang, W. W. (2015) Coronal Properties of the Seyfert 1.9 Galaxy MCG-05-23-016 Determined from Hard X-Ray Spectroscopy with NuSTAR. Astrophysical Journal, 800 (1). Art. No. 62. ISSN 0004-637X. doi:10.1088/0004-637X/800/1/62.

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Measurements of the high-energy cut-off in the coronal continuum of active galactic nuclei have long been elusive for all but a small number of the brightest examples. We present a direct measurement of the cut-off energy in the nuclear continuum of the nearby Seyfert 1.9 galaxy MCG–05-23-016 with unprecedented precision. The high sensitivity of NuSTAR up to 79 keV allows us to clearly disentangle the spectral curvature of the primary continuum from that of its reflection component. Using a simple phenomenological model for the hard X-ray spectrum, we constrain the cut-off energy to 116^(+6)_(-5) keV with 90% confidence. Testing for more complex models and nuisance parameters that could potentially influence the measurement, we find that the cut-off is detected robustly. We further use simple Comptonized plasma models to provide independent constraints for both the kinetic temperature of the electrons in the corona and its optical depth. At the 90% confidence level, we find kT_e = 29  ±  2 keV and τ_e = 1.23 ± 0.08 assuming a slab (disk-like) geometry, and kT_e = 25 ± 2 keV and τe = 3.5 ± 0.2 assuming a spherical geometry. Both geometries are found to fit the data equally well and their two principal physical parameters are correlated in both cases. With the optical depth in the τ_e ≳ 1 regime, the data are pushing the currently available theoretical models of the Comptonized plasma to the limits of their validity. Since the spectral features and variability arising from the inner accretion disk have been observed previously in MCG–05-23-016, the inferred high optical depth implies that a spherical or disk-like corona cannot be homogeneous.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Matt, G.0000-0002-2152-0916
Harrison, F. A.0000-0003-2992-8024
Zoghbi, A.0000-0002-0572-9613
Ballantyne, D. R.0000-0001-8128-6976
Boggs, S. E.0000-0001-9567-4224
Christensen, F. E.0000-0001-5679-1946
Fabian, A. C.0000-0002-9378-4072
Fürst, F.0000-0003-0388-0560
Parker, M. L.0000-0002-8466-7317
Stern, D.0000-0003-2686-9241
Walton, D. J.0000-0001-5819-3552
Zhang, W. W.0000-0002-1426-9698
Additional Information:© 2015. The American Astronomical Society. Received 16 July 2014; accepted for publication 17 December 2014; Published 9 February 2015. M.B. acknowledges support from the International Fulbright Science and Technology Award. A.M. and G.M. acknowledge financial support from the 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 No. 312789. C.S.R. thanks NASA for support under ADAP grant NNX14AF86G. 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 the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA). This research has made use of NASA's Astrophysics Data System.
Funding AgencyGrant Number
International Fulbright Science and Technology AwardUNSPECIFIED
Agenzia Spaziale Italiana (ASI)ASI/INAF I/037/12/0-011/13
European Research Council (ERC)312789
Istituto Nazionale di Astrofisica (INAF)UNSPECIFIED
Subject Keywords:galaxies: active; galaxies: individual (MCG-5-23-016); galaxies: nuclei; galaxies: Seyfert; X-rays: galaxies
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2015-81
Issue or Number:1
Record Number:CaltechAUTHORS:20150316-084932916
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Official Citation:Coronal Properties of the Seyfert 1.9 Galaxy MCG-05-23-016 Determined from Hard X-Ray Spectroscopy with NuSTAR M. Baloković et al. 2015 ApJ 800 62
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:55767
Deposited On:16 Mar 2015 21:06
Last Modified:10 Nov 2021 20:49

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