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NuSTAR and XMM-NEWTON Observations of NGC 1365: Extreme Absorption Variability and a Constant Inner Accretion Disk

Walton, D. J. and Harrison, F. A. and Fuerst, F. and Grefenstette, B. W. and Madsen, K. K. and Rivers, E. (2014) NuSTAR and XMM-NEWTON Observations of NGC 1365: Extreme Absorption Variability and a Constant Inner Accretion Disk. Astrophysical Journal, 788 (1). Art. No. 76. ISSN 0004-637X. http://resolver.caltech.edu/CaltechAUTHORS:20140707-144535458

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Abstract

We present a spectral analysis of four coordinated NuSTAR+XMM-Newton observations of the Seyfert galaxy NGC 1365. These exhibit an extreme level of spectral variability, which is primarily due to variable line-of-sight absorption, revealing relatively unobscured states in this source for the first time. Despite the diverse range of absorption states, each of the observations displays the same characteristic signatures of relativistic reflection from the inner accretion disk. Through time-resolved spectroscopy, we find that the strength of the relativistic iron line and the Compton reflection hump relative to the intrinsic continuum are well correlated, which is expected if they are two aspects of the same broadband reflection spectrum. We apply self-consistent disk reflection models to these time-resolved spectra in order to constrain the inner disk parameters, allowing for variable, partially covering absorption to account for the vastly different absorption states that were observed. Each of the four observations is treated independently to test the consistency of the results obtained for the black hole spin and the disk inclination, which should not vary on observable timescales. We find both the spin and the inclination determined from the reflection spectrum to be consistent, confirming that NGC 1365 hosts a rapidly rotating black hole; in all cases the dimensionless spin parameter is constrained to be a* > 0.97 (at 90% statistical confidence or better.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://arxiv.org/abs/1404.5620arXivDiscussion Paper
http://dx.doi.org/10.1088/0004-637X/788/1/76 DOIArticle
http://iopscience.iop.org/0004-637X/788/1/76/PublisherArticle
ORCID:
AuthorORCID
Harrison, F. A.0000-0003-2992-8024
Madsen, K. K.0000-0003-1252-4891
Additional Information:© 2014 The American Astronomical Society. Received 2013 November 27; accepted 2014 April 18; published 2014 May 23. The authors would like to thank the referee for providing useful feedback, which helped improve the manuscript. This research has made use of data obtained with the NuSTAR mission, a project led by the California Institute of Technology (Caltech), managed by the Jet Propulsion Laboratory (JPL) and funded by NASA, and XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. We thank both the XMM Newton and the NuSTAR Operations, Software, and Calibration teams for support with the execution and analysis of these coordinated observations. This research was supported under NASA grant No. NNG08FD60C and has made use of the NuSTAR Data Analysis Software (NUSTARDAS) jointly developed by the ASI Science Data Center (ASDC, Italy) and Caltech (USA). P.A. acknowledges financial support from Conicyt ACT 1101, and P.G. acknowledges support from STFC (grant reference ST/J00369711). Facilites: NuSTAR, XMM
Group:NuSTAR, Space Radiation Laboratory
Funders:
Funding AgencyGrant Number
NASANNG08FD60C
Comisión Nacional de Investigación Científica y Tecnológica (CONICYT)ACT 1101
Science and Technology Facilities Council (STFC)ST/J00369711
Subject Keywords:black hole physics; galaxies : active; X-rays : individual (NGC 1365)
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2014-52
Record Number:CaltechAUTHORS:20140707-144535458
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20140707-144535458
Official Citation:NuSTAR and XMM-NEWTON Observations of NGC 1365: Extreme Absorption Variability and a Constant Inner Accretion Disk D. J. Walton et al. 2014 ApJ 788 76
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:46906
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:07 Jul 2014 23:02
Last Modified:18 Nov 2016 01:02

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