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On the Nature of the High-Energy Rollover in 1H 0419-577

Turner, T. J. and Reeves, J. N. and Braito, V. and Costa, M. (2018) On the Nature of the High-Energy Rollover in 1H 0419-577. Monthly Notices of the Royal Astronomical Society, 476 (1). pp. 1258-1270. ISSN 0035-8711. doi:10.1093/mnras/sty318.

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A NuSTAR/Swift observation of the luminous Seyfert 1 galaxy 1H 0419-577 taken during 2015 reveals one of the most extreme high-energy cut-offs observed to date from an AGN – an origin due to thermal Comptonization would imply a remarkably low coronal temperature kT ∼ 15 keV. The low-energy peak of the spectrum in the hard X-ray NuSTAR band, which peaks before the expected onset of a Compton hump, rules out strong reflection as the origin of the hard excess in this AGN. We show the origin of the high-energy rollover is likely due to a combination of both thermal Comptonization and an intrinsically steeper continuum, which is modified by absorption at lower energies. Furthermore, modelling the broad-band XUV continuum shape as a colour-corrected accretion disc, requires the presence of a variable warm absorber to explain all flux and spectral states of the source, consistent with the previous work on this AGN. While absorber variations produce marked spectral variability in this AGN, consideration of all flux states allows us to isolate a colourless component of variability that may arise from changes in the inner accretion flow, typically at around 10 r_g.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Turner, T. J.0000-0003-2971-1722
Braito, V.0000-0002-2629-4989
Additional Information:© 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2018 February 2. Received 2018 February 1; in original form 2017 September 15. Published: 09 February 2018. TJT acknowledges NASA grant NNH13CH63C. JNR acknowledges NASA grant NNX15AV18G. We are grateful to the NuSTAR operations team for performing this observation and providing software and calibration for the data analysis. We thank the anonymous referee for comments which improved this manuscript. This research has also made use of data obtained from the High Energy Astrophysics Science Archive Research Center (HEASARC), provided by NASA’s Goddard Space Flight Center and from the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA.
Subject Keywords:galaxies: active – quasars: individual: 1H 0419-577 – galaxies: Seyfert –X-rays: galaxies
Issue or Number:1
Record Number:CaltechAUTHORS:20180207-091935800
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Official Citation:T J Turner, J N Reeves, V Braito, M Costa; On the nature of the high-energy rollover in 1H 0419-577, Monthly Notices of the Royal Astronomical Society, Volume 476, Issue 1, 1 May 2018, Pages 1258–1270,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:84710
Deposited By: Joy Painter
Deposited On:07 Feb 2018 17:24
Last Modified:15 Nov 2021 20:22

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