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NuSTAR spectral analysis of two bright Seyfert 1 galaxies: MCG +8-11-11 and NGC 6814

Tortosa, A. and Bianchi, S. and Marinucci, A. and Matt, G. and Middei, R. and Piconcelli, E. and Brenneman, L. W. and Cappi, M. and Dadina, M. and De Rosa, A. and Petrucci, P. O. and Ursini, F. and Walton, D. J. (2018) NuSTAR spectral analysis of two bright Seyfert 1 galaxies: MCG +8-11-11 and NGC 6814. Monthly Notices of the Royal Astronomical Society, 473 (3). pp. 3104-3112. ISSN 0035-8711. doi:10.1093/mnras/stx2457.

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We report on the NuSTAR observations of two bright Seyfert 1 galaxies, namely MCG +8-11-11 (100 ks) and NGC 6814 (150 ks). The main goal of these observations was to investigate the Comptonization mechanisms acting in the innermost regions of an active galactic nucleus (AGN) which are believed to be responsible for the UV/X-ray emission. The spectroscopic analysis of the NuSTAR spectra of these two sources revealed that although they had different properties overall (black hole masses, luminosity and Eddington ratios), they had very similar coronal properties. Both presented a power-law spectrum with a high-energy cut-off at ∼150–200 keV, a relativistically broadened Fe K α line and the associated disc reflection component, plus a narrow iron line likely emitted in Compton thin and distant matter. The intrinsic continuum was well described by Comptonization models that show for MCG +8-11-11 a temperature of the coronal plasma of kT_e ∼ 60 keV and an extrapolated optical depth τ = 1.8; for NGC 6814, the coronal temperature was kT_e ∼ 45 keV with an extrapolated optical depth of τ = 2.5. We compare and discuss these values to some most common Comptonization models that aim at explaining the energy production and stability of coronae in AGNs.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Bianchi, S.0000-0002-4622-4240
Matt, G.0000-0002-2152-0916
Middei, R.0000-0001-9815-9092
Piconcelli, E.0000-0001-9095-2782
De Rosa, A.0000-0001-5668-6863
Walton, D. J.0000-0001-5819-3552
Additional Information:© 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2017 September 20; Received 2017 September 20; in original form 2017 July 14; Published: 02 October 2017. We thank the anonymous referee for comments that helped improving the clarity of the paper. 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 NuSTARDAS jointly developed by the ASDC (Italy) and the California Institute of Technology (USA). AT, AM and GM acknowledge financial support from Italian Space Agency under grant ASI/INAF I/037/12/0-011/13, and SB under grant ASI-INAF I/037/12/P1. Part of this work is based on archival data, software or online services provided by the ASDC. AT, SB, AM, GM and RM acknowledge financial support from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 312789. POP acknowledges financial support from the CNES and the CNRS/PNHE. EP and SB acknowledge financial contribution from the agreement ASI-INAF I/037/12/0.
Funding AgencyGrant Number
Agenzia Spaziale Italiana (ASI)I/037/12/0-011/13
Agenzia Spaziale Italiana (ASI)I/037/12/P1
European Research Council (ERC)312789
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Agenzia Spaziale Italiana (ASI)I/037/12/0
Subject Keywords:galaxies: active – galaxies: individual: MCG +8-11-11 – galaxies: individual: NGC 6814 – galaxies: Seyfert –X-rays: galaxies
Issue or Number:3
Record Number:CaltechAUTHORS:20170924-172902877
Persistent URL:
Official Citation:A. Tortosa, S. Bianchi, A. Marinucci, G. Matt, R. Middei, E. Piconcelli, L. W. Brenneman, M. Cappi, M. Dadina, A. De Rosa, P. O. Petrucci, F. Ursini, D. J. Walton; NuSTAR spectral analysis of two bright Seyfert 1 galaxies: MCG +8-11-11 and NGC 6814, Monthly Notices of the Royal Astronomical Society, Volume 473, Issue 3, 21 January 2018, Pages 3104–3112,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:81788
Deposited By: Joy Painter
Deposited On:25 Sep 2017 18:09
Last Modified:15 Nov 2021 19:46

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