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Parameter constraints in a near-equipartition model with multifrequency NuSTAR, Swift, and Fermi-LAT data from 3C 279

Yan, Dahai and Zhang, Li and Zhang, Shuang-Nan (2015) Parameter constraints in a near-equipartition model with multifrequency NuSTAR, Swift, and Fermi-LAT data from 3C 279. Monthly Notices of the Royal Astronomical Society, 454 (2). pp. 1310-1319. ISSN 0035-8711. http://resolver.caltech.edu/CaltechAUTHORS:20160131-145440789

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Abstract

Precise spectra of 3C 279 in the 0.5–70 keV range, obtained during two epochs of Swift and NuSTAR observations, are analysed using a near-equipartition model. We apply a one-zone leptonic model with a three-parameter log-parabola electron energy distribution to fit the Swift and NuSTAR X-ray data, as well as simultaneous optical and Fermi-LAT gamma-ray data. The Markov chain Monte Carlo technique is used to search the high-dimensional parameter space and evaluate the uncertainties on model parameters. We show that the two spectra can be successfully fitted in near-equipartition conditions, defined by the ratio of the energy density of relativistic electrons to magnetic field ζe being close to unity. In both spectra, the observed X-rays are dominated by synchrotron self-Compton photons, and the observed gamma-rays are dominated by Compton scattering of external infrared photons from a surrounding dusty torus. Model parameters are well constrained. From the low state to the high state, both the curvature of the log-parabola width parameter and the synchrotron peak frequency significantly increase. The derived magnetic fields in the two states are nearly identical (∼1 G), but the Doppler factor in the high state is larger than that in the low state (∼28 versus ∼18). We derive that the gamma-ray emission site takes place outside the broad-line region, at ≳0.1 pc from the black hole, but within the dusty torus. Implications for 3C 279 as a source of high-energy cosmic rays are discussed.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://mnras.oxfordjournals.org/content/454/2/1310PublisherArticle
http://dx.doi.org/10.1093/mnras/stv2091DOIArticle
Additional Information:© 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2015 September 7. Received 2015 September 4; in original form 2015 June 23. First published online October 1, 2015. We would like to give special thanks to Charles Dermer, who carefully edited the manuscript and gave us many valuable suggestions and comments. We thank Charles Dermer, J. Finke, Kinwah Wu for discussions, and the anonymous referee for very helpful and constructive questions. We are grateful to Krzysztof Nalewajko for providing us the data of 3C 279. This work is partially supported by the National Natural Science Foundation of China (NSFC 11433004) and Top Talents Program of Yunnan Province, China. DHY acknowledges partial funding support by China Postdoctoral Science Foundation under grant no. 2015M570152. SNZ acknowledges partial funding support by 973 Program of China under grant 2014CB845802, by the National Natural Science Foundation of China (NSFC) under grant nos. 11133002 and 11373036, by the Qianren start-up grant 292012312D1117210, and by the Strategic Priority Research Program ‘The Emergence of Cosmological Structures’ of the Chinese Academy of Sciences (CAS) under grant no. XDB09000000. We acknowledge the use of the ASDC web tools (SED Builder, http://tools.asdc.asi.it).
Group:NuSTAR
Funders:
Funding AgencyGrant Number
National Natural Science Foundation of China (NSFC)11433004
973 Program of China2014CB845802
National Natural Science Foundation of China (NSFC)11133002
National Natural Science Foundation of China (NSFC)11373036
Qianren292012312D1117210
Chinese Academy of SciencesXDB09000000
Record Number:CaltechAUTHORS:20160131-145440789
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20160131-145440789
Official Citation:Dahai Yan, Li Zhang, and Shuang-Nan Zhang Parameter constraints in a near-equipartition model with multifrequency NuSTAR, Swift, and Fermi-LAT data from 3C 279 MNRAS (December 01, 2015) Vol. 454 1310-1319 doi:10.1093/mnras/stv2091 First published online October 1, 2015
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:64111
Collection:CaltechAUTHORS
Deposited By: Joy Painter
Deposited On:03 Feb 2016 00:50
Last Modified:03 Feb 2016 00:50

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