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Published June 20, 2015 | Submitted + Published
Journal Article Open

NuSTAR and Suzaku X-Ray Spectroscopy of NGC 4151: Evidence for Reflection from the Inner Accretion Disk

Abstract

We present X-ray timing and spectral analyses of simultaneous 150 ks Nuclear Spectroscopic Telescope Array (NuSTAR) and Suzaku X-ray observations of the Seyfert 1.5 galaxy NGC 4151. We disentangle the continuum emission, absorption, and reflection properties of the active galactic nucleus (AGN) by applying inner accretion disk reflection and absorption-dominated models. With a time-averaged spectral analysis, we find strong evidence for relativistic reflection from the inner accretion disk. We find that relativistic emission arises from a highly ionized inner accretion disk with a steep emissivity profile, which suggests an intense, compact illuminating source. We find a preliminary, near-maximal black hole spin_(ɑ > 0.9) accounting for statistical and systematic modeling errors. We find a relatively moderate reflection fraction with respect to predictions for the lamp post geometry, in which the illuminating corona is modeled as a point source. Through a time-resolved spectral analysis, we find that modest coronal and inner disk reflection (IDR) flux variation drives the spectral variability during the observations. We discuss various physical scenarios for the IDR model and we find that a compact corona is consistent with the observed features.

Additional Information

© 2015 American Astronomical Society. Received 2014 September 30; accepted 2015 April 27; published 2015 June 15. 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. This research made use of the NuSTAR Data Analysis Software (NuSTAR-DAS) jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (Caltech, USA). M.L.K. gratefully acknowledges support through NASA grant #NNX13AE90G. G.M. and 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. C.S.R. acknowledges support from the NASA-ADAP program under grants NNX14AF86G and NNX14AF89G. F.E.B. acknowledges support from CONICYT-Chile (Basal-CATA PFB-06/2007, FONDECYT 1141218, Anillo ACT1101) and ICM grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS. We thank Alan Marscher for helpful discussions. We thank the anonymous referee for comments, which have improved this manuscript. This research made use of Astropy, a community-developed core Python package for Astronomy (Astropy Collaboration et al. 2013), and Matplotlib (Hunter 2007). Facilities:NuSTAR (FPMA, FPMB), Suzaku (XIS, HXD)

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Published - 0004-637X_806_2_149.pdf

Submitted - 1504.07950v1.pdf

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August 22, 2023
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