NuSTAR Observations of Candidate Subparsec Binary Supermassive Black Holes
Creators
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1.
University of California, Los Angeles
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2.
Universities Space Research Association
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3.
California Institute of Technology
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4.
Jet Propulsion Lab
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Harvard-Smithsonian Center for Astrophysics
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6.
University of Copenhagen
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7.
American Museum of Natural History
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Borough of Manhattan Community College
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9.
The Graduate Center, CUNY
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10.
Columbia University
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Seoul National University
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Research Institute in Astrophysics and Planetology
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13.
Arcetri Astrophysical Observatory
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University of Hertfordshire
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15.
University of Cambridge
Abstract
We present an analysis of NuSTAR X-ray observations of three active galactic nuclei (AGN) that were identified as candidate subparsec binary supermassive black hole (SMBH) systems in the Catalina Real-Time Transient Survey based on apparent periodicity in their optical light curves. Simulations predict that close-separation accreting SMBH binaries will have different X-ray spectra than single accreting SMBHs. We previously observed these AGN with Chandra and found no differences between their low-energy X-ray properties and the larger AGN population. However, some models predict differences to be more prominent at energies higher than probed by Chandra. We find that even at the higher energies probed by NuSTAR, the spectra of these AGN are indistinguishable from the larger AGN population. This could rule out models predicting large differences in the X-ray spectra in the NuSTAR bands. Alternatively, it might mean that these three AGN are not binary SMBHs.
Copyright and License
© 2024. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Acknowledgement
We thank Julian Krolik for helpful comments that have improved the paper. The scientific results reported in this article are based on data obtained from the Chandra Data Archive. This work is based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. We acknowledge the use of public data from the Swift data archive. The scientific results reported in this paper are based on data obtained from the Chandra Data Archive (ObsID 19528). This research has made use of data and/or software provided by the High Energy Astrophysics Science Archive Research Center (HEASARC), which is a service of the Astrophysics Science Division at NASA/GSFC and the High Energy Astrophysics Division of the Smithsonian Astrophysical Observatory. This work has made use of data obtained from the NuSTAR mission, a project led by Caltech, funded by NASA, and managed by NASA/JPL. D.J.D. received funding from the European Union's Horizon 2020 research and innovation program under Marie Sklodowska-Curie grant agreement No. 101029157 and from the Danish Independent Research Fund through Sapere Aude Starting grant No. 121587. Z.H. acknowledges support from NASA ATP grant 80NSSC22K082.
Facilities
CXO - Chandra X-ray Observatory satellite, NuSTAR - The NuSTAR (Nuclear Spectroscopic Telescope Array) mission, XMM - Newton X-Ray Multimirror Mission satellite, Swift - Swift Gamma-Ray Burst Mission
Software References
HEASOFT (Nasa High Energy Astrophysics Science Archive Research Center (Heasarc), 2014), CIAO (Fruscione et al. 2006), XMM-Newton SAS (Gabriel et al. 2004)
Files
Saade_2024_ApJ_966_104.pdf
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Additional details
Identifiers
- ISSN
- 1538-4357
Funding
- European Research Council
- Marie Skłodowska-Curie Fellowship 101029157
- Danmarks Frie Forskningsfond
- 121587
- National Aeronautics and Space Administration
- 80NSSC22K082